Inner Selects vs. Outer Joins

We have a report where we are joining many tables (25 tables) together. Initially, we created the report with outer joins and noticed that the cost of the explain plan was 2600 and the performance was adequate. We then started to remove the outer joins and replacing with inner selects and the cost and performance of the report improved. Currently, we have replaced 13 of the outer joins with inner selects and the cost is down to 650.
Typically, I have always used joins or outer joins because I thought this was best practice. However, I am now questioning this.
Is it better to use inner selects when you are only returning one column from a table?
Other than tables that require multiple columns to be returned, are there issues we should be concerned with?
Below are examples:
Thanks,
Brian
-- Using Outer Joins
Select q.quote_id, q.quote_name, l.location_name, sr.sales_rep_name
from quote q, location l, sales_rep sr
where q.location_id = l.loation_id (+)
and q.sales_rep_id = sr.sales_rep_id (+)
-- Using Inner Selects
Select q.quote_id, q.quote_name,
(select location_name from location where location_id = q.location_id) location_name,
(select sales_rep_name from sales_rep where sales_rep_id = q.sales_rep_id) sales_rep_name
from quote q

The cost of a query does not mean better performance. The scalar subqueries that you use when rewriting that query show up in your explain plan with no cost at all, and this is just no true. (a query must "cost" something, right?)
Instead of starting to rewrite your queries using scalara subqueries, it's better to investigate why a query performs bad.
If using scalar subquery would always yield a better performance, Oracle would probably rewrite all outer join queries to using scalar subquery.

Similar Messages

Using Left Outer Join

Hi SAP,
I have an access database with table called "Employee_ID". I am linking this table to a table called "Sales" in our main database and trying to report on January 2009.
There is one employee that is not appearing in my report. I know this employee has had no sales in Jan 2009. So, I tried linking the table using Left Outer Join and still this employee is not appearing in my report.
As a test, when I bring in Employee_ID table alone, the missing employee appears but when I try linking it INNER or LEFT OUTER join to table Sales, this employee does not appear.
Any help how I can bring the employee in from table Employee_ID?
Many thanks in advance,
Zack H.

Carl & Raghavendra,
Your suggestion led me to the finding my solution. Your suggestion brought back the missing employee but I needed all employees that had sales in January 2009 AND those that didn't. So I had to tweak your select expert formula as follows:
isnull({Sales.amt}) or
{Sales.period}="0109"
This brought back everything as needed! There was one negative about using this method. The performance was poor. It took a really long time to run.
To avoid having to wait for this to run and increase the performance, I had to go into the database and add a $0.00 sales amt for employee 2040 (or an empty sales amount record) in the month of January 2009. This brought back everyone also and it obviously increased the performance exponentially. Curious, why does it take forever to run using the above formula in select expert?
Thank you both Raghavendra and Carl for your relentless efforts to find a solution. You did it!
Zack H.

BLS - Full Outer Join

What would cause a JOIN action block to fail when I try to do a FULL OUTER JOIN? The join works when I select an inner join or an outer join. If I select full outer join, I get the error:
[ERROR]: Joiner: Index: 14, Size: 14
[ERROR]: ACTION FAILED: End Action Join_Open : (Joiner)
Thanks

What version/build are you using?
Regards,
Jamie

Dynamic From statement in select query and/or outer join not working

Dear Experts, I have a select query where the select columns are dynamic, the where condition is also dynamic. It is of the below format:
Select (dynamic columns) INTO <wa>
FROM a inner join b on af1 = bf1
inner join c on af2 = cf2......
WHERE (dynamic conditios)
ORDER BY ( dynamic sort condition).
Now I have to include some tables (dynamically depending on the user input) in the inner join statement which will give description for the selected fields. And these database tables may or may no be empty. So in this case, my select query will not return any data if these tables are empty. And I dont want that.
I tried using outer join for the extra tables but it gave me a runtime error. I also tried forming the inner join statement dynamically but it was not supporting.
Kindly give me pointers.
Thanks

Hey thanks for the reply, but the problem is not solved.
I am already using ( fileds, value) like table in my where condition and the select statement was working properly.
the problem is that now I have to include some tables in the join statement which can be empty and so i want to use Outer join.
But I am getting a runtime error as below:
Error analysis
    An exception occurred that is explained in detail below.
    The exception, which is assigned to class 'CX_SY_DYNAMIC_OSQL_SYNTAX', was not
     caught in
    procedure "ZATSCSNG_RFC_READ_TABLE" "(FUNCTION)", nor was it propagated by a
     RAISING clause.
    Since the caller of the procedure could not have anticipated that the
    exception would occur, the current program is terminated.
    The reason for the exception is:
    The running ABAP program wanted to execute a SELECT statement whose
    WHERE condition was (partly) specified dynamically. The part that is
    specified in an internal table at runtime is compared to a field of the
    right table of an LEFT OUTER JOIN. Such comparisons are not supported by
     all database systems and are therefore not allowed.

How to do outer join select query for an APEX report

Hello everyone,
I am Ann.
I have one select statement that calculate the statistics for one month(October 2012 in this example)
select ph.phase_number
, sum ( (case
WHEN ph.date_finished IS NULL OR ph.date_finished > last_day(TO_DATE('Oct 2012','MON YYYY'))
THEN last_day(TO_DATE('Oct 2012','MON YYYY'))
ELSE ph.date_finished
END )
- ph.date_started + 1) / count(def.def_id) as avg_days
from phase_membership ph
inner join court_engagement ce on ph.mpm_eng_id = ce.engagement_id
inner join defendant def on ce.defendant_id = def.def_id
where def.active = 1
and ph.date_started <= last_day(TO_DATE('Oct 2012','MON YYYY'))
and ph.active = 1
and UPPER(ce.court_name) LIKE '%'
group by rollup(phase_number)
Result is as below
Phase_Number     AVG_DAYS
Phase One     8.6666666666666667
Phase Two     14.6
Phase Three     12
     11.4615365
I have other select list mainly list the months between two date value.
select to_char(which_month, 'MON YYYY') as display_month
from (
select add_months(to_date('Aug 2012','MON YYYY'), rownum-1) which_month
from all_objects
where
rownum <= months_between(to_date('Oct 2012','MON YYYY'), add_months(to_date('Aug 2012','MON YYYY'), -1))
order by which_month )
Query result is as below
DISPLAY_MONTH
AUG 2012
SEP 2012
OCT 2012
Is there any way that I can join these two select statement above to generate a result like:
Month          Phase Number     Avg days
Aug 2012     Phase One     8.666
Sep 2012     Phase One     7.66
Oct 2012     Phase One     5.66
Aug 2012     Phase Two     8.666
Sep 2012     Phase Two     7.66
Oct 2012     Phase Two     5.66
Aug 2012     Phase Three     8.666
Sep 2012     Phase Three     7.66
Oct 2012     Phase Three     5.66
Or
Month          Phase Number     Avg days
Aug 2012     Phase One     8.666
Aug 2012     Phase Two     7.66
Aug 2012     Phase Three     5.66
Sep 2012     Phase One     8.666
Sep 2012     Phase Two     7.66
Sep 2012     Phase Three     5.66
Oct 2012     Phase One     8.666
Oct 2012     Phase Two     7.66
Oct 2012     Phase Three     5.66
And it can be order by either Phase Number or Month.
My other colleague suggest I should use an left outer join but after trying so many ways, I am still stuck.
One of the select I tried is
select a.display_month,b.* from (
select to_char(which_month, 'MON YYYY') as display_month
from (
select add_months(to_date('Aug 2012','MON YYYY'), rownum-1) which_month
from all_objects
where
rownum <= months_between(to_date('Oct 2012','MON YYYY'), add_months(to_date('Aug 2012','MON YYYY'), -1))
order by which_month )) a left outer join
( select to_char(ph.date_finished,'MON YYYY') as join_month, ph.phase_number
, sum ( (case
WHEN ph.date_finished IS NULL OR ph.date_finished > last_day(TO_DATE(a.display_month,'MON YYYY'))
THEN last_day(TO_DATE(a.display_month,'MON YYYY'))
ELSE ph.date_finished
END )
- ph.date_started + 1) / count(def.def_id) as avg_days
from phase_membership ph
inner join court_engagement ce on ph.mpm_eng_id = ce.engagement_id
inner join defendant def on ce.defendant_id = def.def_id
where def.active = 1
and ph.date_started <= last_day(TO_DATE(a.display_month,'MON YYYY'))
and ph.active = 1
and UPPER(ce.court_name) LIKE '%'
group by to_char(ph.date_finished,'MON YYYY') , rollup(phase_number)) b
on a.display_month = b.join_month
but then I get an error
SQL Error: ORA-00904: "A"."DISPLAY_MONTH": invalid identifier
I need to display a report on APEX with option for people to download at least CSV format.
I already have 1 inteactive report in the page, so don’t think can add another interactive report without using the iframe trick.
If any of you have any ideas, please help.
Thanks a lot.
Ann

First of all, a huge thanks for following this Frank.
I have just started working here, I think the Oracle version is 11g, but not sure.
To run Oracle APEX version 4, I think they must have at least 10g R2.
This report is a bit challenging for me.I has never worked with PARTITION before.
About the select query you suggested, I run , and it seems working fine, but if I try this,
it return error ORA-01843: not a valid month
DEFINE startmonth = "Aug 2012";
DEFINE endmonth   = "Oct 2012";
WITH     all_months     AS
     select add_months(to_date('&startmonth','MON YYYY'), rownum-1) AS which_month
     ,      add_months(to_date('&startmonth','MON YYYY'), rownum ) AS next_month
     from all_objects
     where
     rownum <= months_between(to_date('&endmonth','MON YYYY'), add_months(to_date('&startmonth','MON YYYY'), -1))
select TO_CHAR (am.which_month, 'Mon YYYY')     AS month
,      ph.phase_number
, sum ( (case
WHEN ph.date_finished IS NULL OR ph.date_finished > last_day(TO_DATE(am.which_month,'MON YYYY'))
THEN last_day(TO_DATE(am.which_month,'MON YYYY'))
ELSE ph.date_finished
END )
- ph.date_started + 1) / count(def.def_id) as avg_days
FROM           all_months         am
LEFT OUTER JOIN phase_membership ph PARTITION BY (ph.phase_number)
                                    ON am.which_month <= ph.date_started
                           AND am.next_month > ph.date_started
                           AND ph.date_started <= last_day(TO_DATE(am.which_month,'MON YYYY')) -- May not be needed
                           AND ph.active = 1
LEFT OUTER join court_engagement ce on ph.mpm_eng_id = ce.engagement_id
                                    and ce.court_name IS NOT NULL -- or something involving LIKE
LEFT OUTER join defendant         def on ce.defendant_id = def.def_id
                                    AND def.active = 1
group by rollup(phase_number, am.which_month)
ORDER BY am.which_month
,            ph.phase_number
;Here is the shorted versions of the three tables:
A_DEFENDANT, A_ENGAGEMENT, A_PHASE_MEMBERSHIP
CREATE TABLE "A_DEFENDANT"
    "DEF_ID"     NUMBER NOT NULL ENABLE,
    "FIRST_NAME" VARCHAR2(50 BYTE),
    "SURNAME"    VARCHAR2(20 BYTE) NOT NULL ENABLE,
    "DOB" DATE NOT NULL ENABLE,
    "ACTIVE" NUMBER(2,0) DEFAULT 1 NOT NULL ENABLE,
    CONSTRAINT "A_DEFENDANT_PK" PRIMARY KEY ("DEF_ID"))
Sample Data
Insert into A_DEFENDANT (DEF_ID,FIRST_NAME,SURNAME,DOB,ACTIVE) values (101,'Joe','Bloggs',to_date('12/12/99','DD/MM/RR'),1);
Insert into A_DEFENDANT (DEF_ID,FIRST_NAME,SURNAME,DOB,ACTIVE) values (102,'John','Smith',to_date('20/05/00','DD/MM/RR'),1);
Insert into A_DEFENDANT (DEF_ID,FIRST_NAME,SURNAME,DOB,ACTIVE) values (103,'Jane','Black',to_date('15/02/98','DD/MM/RR'),1);
Insert into A_DEFENDANT (DEF_ID,FIRST_NAME,SURNAME,DOB,ACTIVE) values (104,'Minnie','Mouse',to_date('13/12/88','DD/MM/RR'),0);
Insert into A_DEFENDANT (DEF_ID,FIRST_NAME,SURNAME,DOB,ACTIVE) values (105,'Daisy','Duck',to_date('05/08/00','DD/MM/RR'),1);
CREATE TABLE "A_ENGAGEMENT"
    "ENGAGEMENT_ID" NUMBER NOT NULL ENABLE,
    "COURT_NAME"    VARCHAR2(50 BYTE) NOT NULL ENABLE,
    "DATE_REFERRED" DATE,
    "DETERMINATION_HEARING_DATE" DATE,
    "DATE_JOINED_COURT" DATE,
    "DATE_TREATMENT_STARTED" DATE,
    "DATE_TERMINATED" DATE,
    "TERMINATION_TYPE" VARCHAR2(50 BYTE),
    "ACTIVE"           NUMBER(2,0) DEFAULT 1 NOT NULL ENABLE,
    "DEFENDANT_ID"     NUMBER,
    CONSTRAINT "A_ENGAGEMENT_PK" PRIMARY KEY ("ENGAGEMENT_ID"))
Insert into A_ENGAGEMENT (ENGAGEMENT_ID,COURT_NAME,DATE_REFERRED,DETERMINATION_HEARING_DATE,DATE_JOINED_COURT,DATE_TREATMENT_STARTED,DATE_TERMINATED,TERMINATION_TYPE,ACTIVE,DEFENDANT_ID) values (1,'AA',to_date('12/08/12','DD/MM/RR'),null,to_date('12/08/12','DD/MM/RR'),null,null,null,1,101);
Insert into A_ENGAGEMENT (ENGAGEMENT_ID,COURT_NAME,DATE_REFERRED,DETERMINATION_HEARING_DATE,DATE_JOINED_COURT,DATE_TREATMENT_STARTED,DATE_TERMINATED,TERMINATION_TYPE,ACTIVE,DEFENDANT_ID) values (2,'BB',to_date('01/09/12','DD/MM/RR'),null,to_date('02/09/12','DD/MM/RR'),null,null,null,1,102);
Insert into A_ENGAGEMENT (ENGAGEMENT_ID,COURT_NAME,DATE_REFERRED,DETERMINATION_HEARING_DATE,DATE_JOINED_COURT,DATE_TREATMENT_STARTED,DATE_TERMINATED,TERMINATION_TYPE,ACTIVE,DEFENDANT_ID) values (3,'AA',to_date('02/09/12','DD/MM/RR'),null,to_date('15/09/12','DD/MM/RR'),null,null,null,1,103);
Insert into A_ENGAGEMENT (ENGAGEMENT_ID,COURT_NAME,DATE_REFERRED,DETERMINATION_HEARING_DATE,DATE_JOINED_COURT,DATE_TREATMENT_STARTED,DATE_TERMINATED,TERMINATION_TYPE,ACTIVE,DEFENDANT_ID) values (4,'BB',to_date('01/10/12','DD/MM/RR'),null,to_date('02/10/12','DD/MM/RR'),null,null,null,1,105);
CREATE TABLE "A_PHASE_MEMBERSHIP"
    "MPM_ID"       NUMBER NOT NULL ENABLE,
    "MPM_ENG_ID"   NUMBER NOT NULL ENABLE,
    "PHASE_NUMBER" VARCHAR2(50 BYTE),
    "DATE_STARTED" DATE NOT NULL ENABLE,
    "DATE_FINISHED" DATE,
    "NOTES" VARCHAR2(2000 BYTE),
    "ACTIVE" NUMBER(2,0) DEFAULT 1 NOT NULL ENABLE,
    CONSTRAINT "A_PHASE_MEMBERSHIP_PK" PRIMARY KEY ("MPM_ID"))
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (1,1,'PHASE ONE',to_date('15/09/12','DD/MM/RR'),to_date('20/09/12','DD/MM/RR'),null,1);
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (2,1,'PHASE TWO',to_date('21/09/12','DD/MM/RR'),to_date('29/09/12','DD/MM/RR'),null,1);
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (3,2,'PHASE ONE',to_date('12/09/12','DD/MM/RR'),null,null,1);
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (4,3,'PHASE ONE',to_date('20/09/12','DD/MM/RR'),to_date('01/10/12','DD/MM/RR'),null,1);
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (5,3,'PHASE TWO',to_date('02/10/12','DD/MM/RR'),to_date('15/10/12','DD/MM/RR'),null,1);
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (6,4,'PHASE ONE',to_date('03/10/12','DD/MM/RR'),to_date('10/10/12','DD/MM/RR'),null,1);
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (7,3,'PHASE THREE',to_date('17/10/12','DD/MM/RR'),null,null,0);
Insert into A_PHASE_MEMBERSHIP (MPM_ID,MPM_ENG_ID,PHASE_NUMBER,DATE_STARTED,DATE_FINISHED,NOTES,ACTIVE) values (8,1,'PHASE THREE',to_date('30/09/12','DD/MM/RR'),to_date('16/10/12','DD/MM/RR'),null,1);
The requirements are:
The user must be able to request the extract for one or more calendar months, e.g.
May 2013
May 2013 – Sep 2013.
The file must contain a separate row for each calendar month in the requested range. Each row must contain the statistics computed for that calendar month.
The file must also include a row of totals.
The user must be able to request the extract for either Waitakere or Auckland or Consolidated (both courts’ statistics accumulated).
Then the part that I am stuck is
For each monitoring phase:
Phase name (e.g. “Phase One”)
Avg_time_in_phase_all_particip
for each phase name,
Add up days in each “phase name” Monitoring Phase, calculated as:
If Monitoring Phase.Date Finished is NULL or > month end date,
+(*Month end date* Minus Monitoring Phase.Date Started Plus 1)+
Otherwise (phase is complete)
+(Monitoring Phase.Date Finished Minus Monitoring Phase.Date Started Plus 1.)+
Divide by the numbers of all participants who have engaged in “phase name”.
This is the words of the Business Analyst,
I try to do as required but still struggle to identify end_month for the above formula to display for the range of months.
Of course, I can write two nested cursor. The first one run the list of month, then for each month, run the parameterised report.
But I prefer if possible just use SQL statements, or at least a PL/SQL but return a query.
With this way, I can create an APEX report, and use their CSV Extract function.
Yes, you are right, court_name is one of the selection parameters.
And the statistics is not exactly for one month. It is kind of trying to identify all phases that are running through the specified month (even phase.date_started is before the month start).
This is the reason why I put the condition AND ph.date_started <= last_day(TO_DATE('Oct 2012','MON YYYY')) (otherwise I get negative avg_days)
User can choose either one court "AA" or "BB" or combined which is all figures.
Sorry for bombarding you a lot of information.
Thanks a lot, again.
Edited by: Ann586341 on Oct 29, 2012 9:57 PM
Edited by: Ann586341 on Oct 29, 2012 9:59 PM

Union among multiple select queries with full outer join

Hello everyone,
I have 3 different select queries (used FULL Outer Join) which work fine. Now I want to add Union to the results among them and pick the selected columns from each query in the final result. while doing so, I am getting an error as "right parenthesis missing". I am quite sure, it is not the real cause. I guess might be issue with the query structure.
select j.pod, j.hostname, portal.hostname,saasc.hostname,a3s.hostname from -- * from
Select J.Pod,J.Hostname, P.Pod Portal_Pod,P.Hostname Portal_Hostname
From Total_Pod J
full outer join Portal_Tmp P On (J.Pod = P.Pod And J.Hostname = P.Hostname) as portal
Union
Select J.Pod,J.Hostname, s.Pod saasc_Pod,s.Hostname saasc_Hostname
From Total_Pod J
full outer join Saasc_Tmp S On (J.Pod = s.Pod And J.Hostname = s.Hostname) as saasc
Union
Select J.Pod,J.Hostname, a.Pod a3s_Pod,a.Hostname a3s_Hostname
From Total_Pod J
Full Outer Join A3s_Tmp A On (J.Pod = A.Pod And J.Hostname = A.Hostname) as a3s
)p.s: select * from (INNER QUERY); also does not work.
Any help appreciated.
Thanks in advance.

With T as
(Select J.Pod,J.Hostname, P.Pod Portal_Pod,P.Hostname Portal_Hostname
From Total_Pod J
full outer join Portal_Tmp P On (J.Pod = P.Pod And J.Hostname = P.Hostname) ),
U as
(Select J.Pod,J.Hostname, s.Pod saasc_Pod,s.Hostname saasc_Hostname
From Total_Pod J
full outer join Saasc_Tmp S On (J.Pod = s.Pod And J.Hostname = s.Hostname) ),
V as
(Select J.Pod,J.Hostname, a.Pod a3s_Pod,a.Hostname a3s_Hostname
From Total_Pod J
Full Outer Join A3s_Tmp A On (J.Pod = A.Pod And J.Hostname = A.Hostname) )
Select T.Pod,T.Hostname,nvl(T.Portal_Hostname,'Not Available') portal,nvl(U.Saasc_Hostname,'Not Available') saasc,NVL(V.A3s_Hostname,'Not Available') a3s From T,U,V
Where T.Pod = U.Pod
And U.Pod = V.Pod
And T.Hostname = U.Hostname
And U.Hostname = V.Hostname

Difference between inner join and outer join

1.Difference between inner join and outer join
2.wht is the difference in using hide and get crusor value in interactive.
3. Using join is better or views in writting program . Which is better.

Table 1                      Table 2
A
B
C
D
D
E
F
G
H
a1
b1
c1
1
1
e1
f1
g1
h1
a2
b2
c2
1
3
e2
f2
g2
h2
a3
b3
c3
2
4
e3
f3
g3
h3
a4
b4
c4
3
|--|||--|
    Inner Join
    |--||||||||--|
    | A | B | C | D | D | E | F | G | H |
    |--||||||||--|
    | a1 | b1 | c1 | 1 | 1 | e1 | f1 | g1 | h1 |
    | a2 | b2 | c2 | 1 | 1 | e1 | f1 | g1 | h1 |
    | a4 | b4 | c4 | 3 | 3 | e2 | f2 | g2 | h2 |
    |--||||||||--|
Example
Output a list of all flights from Frankfurt to New York between September 10th and 20th, 2001 that are not sold out:
DATA: DATE   LIKE SFLIGHT-FLDATE,
      CARRID LIKE SFLIGHT-CARRID,
      CONNID LIKE SFLIGHT-CONNID.
SELECT FCARRID FCONNID F~FLDATE
    INTO (CARRID, CONNID, DATE)
    FROM SFLIGHT AS F INNER JOIN SPFLI AS P
           ON FCARRID = PCARRID AND
              FCONNID = PCONNID
    WHERE P~CITYFROM = 'FRANKFURT'
      AND P~CITYTO   = 'NEW YORK'
      AND F~FLDATE BETWEEN '20010910' AND '20010920'
      AND FSEATSOCC < FSEATSMAX.
WRITE: / DATE, CARRID, CONNID.
ENDSELECT.
If there are columns with the same name in both tables, you must distinguish between them by prefixing the field descriptor with the table name or a table alias.
Note
In order to determine the result of a SELECT command where the FROM clause contains a join, the database system first creates a temporary table containing the lines that meet the ON condition. The WHERE condition is then applied to the temporary table. It does not matter in an inner join whether the condition is in the ON or WHEREclause. The following example returns the same solution as the previous one.
Example
Output of a list of all flights from Frankfurt to New York between September 10th and 20th, 2001 that are not sold out:
DATA: DATE   LIKE SFLIGHT-FLDATE,
      CARRID LIKE SFLIGHT-CARRID,
      CONNID LIKE SFLIGHT-CONNID.
SELECT FCARRID FCONNID F~FLDATE
    INTO (CARRID, CONNID, DATE)
    FROM SFLIGHT AS F INNER JOIN SPFLI AS P
           ON FCARRID = PCARRID
    WHERE FCONNID = PCONNID
      AND P~CITYFROM = 'FRANKFURT'
      AND P~CITYTO   = 'NEW YORK'
      AND F~FLDATE BETWEEN '20010910' AND '20010920'
      AND FSEATSOCC < FSEATSMAX.
WRITE: / DATE, CARRID, CONNID.
ENDSELECT.
Note
Since not all of the database systems supported by SAP use the standard syntax for ON conditions, the syntax has been restricted. It only allows those joins that produce the same results on all of the supported database systems:
Only a table or view may appear to the right of the JOIN operator, not another join expression.
Only AND is possible in the ON condition as a logical operator.
Each comparison in the ON condition must contain a field from the right-hand table.
If an outer join occurs in the FROM clause, all the ON conditions must contain at least one "real" JOIN condition (a condition that contains a field from tabref1 amd a field from tabref2.
Note
In some cases, '*' may be specified in the SELECT clause, and an internal table or work area is entered into the INTO clause (instead of a list of fields). If so, the fields are written to the target area from left to right in the order in which the tables appear in the FROM clause, according to the structure of each table work area. There can then be gaps between table work areas if you use an Alignment Request. For this reason, you should define the target work area with reference to the types of the database tables, not simply by counting the total number of fields. For an example, see below:
Variant 3
... FROM tabref1 LEFT [OUTER] JOIN tabref2 ON cond
Effect
Selects the data from the transparent database tables and/or views specified in tabref1 and tabref2. tabref1 und tabref2 both have either the same form as in variant 1 or are themselves join expressions. The keyword OUTER can be omitted. The database tables or views specified in tabref1 and tabref2 must be recognized by the ABAP-Dictionary.
In order to determine the result of a SELECT command where the FROM clause contains a left outer join, the database system creates a temporary table containing the lines that meet the ON condition. The remaining fields from the left-hand table (tabref1) are then added to this table, and their corresponding fields from the right-hand table are filled with ZERO values. The system then applies the WHERE condition to the table.
Left outer join between table 1 and table 2 where column D in both tables set the join condition:
Table 1                      Table 2
A
B
C
D
D
E
F
G
H
a1
b1
c1
1
1
e1
f1
g1
h1
a2
b2
c2
1
3
e2
f2
g2
h2
a3
b3
c3
2
4
e3
f3
g3
h3
a4
b4
c4
3
|--|||--|
    Left Outer Join
    |--||||||||--|
    | A | B | C | D | D | E | F | G | H |
    |--||||||||--|
    | a1 | b1 | c1 | 1 | 1 | e1 | f1 | g1 | h1 |
    | a2 | b2 | c2 | 1 | 1 | e1 | f1 | g1 | h1 |
    | a3 | b3 | c3 | 2 |NULL|NULL|NULL|NULL|NULL|
    | a4 | b4 | c4 | 3 | 3 | e2 | f2 | g2 | h2 |
    |--||||||||--|
Regards
Prabhu

What is left join /right join / out join/ inner join/please give example!

what is left join /right join / out join/ inner join/please give example!
thanks

Maybe these examples will give you an idea...
SQL> select * from t1;
        ID
         1
         2
         3
         4
SQL> select * from t2;
        ID
         3
         4
         5
         6
-- LEFT OUTER JOIN
SQL> select t1.id, t2.id
2 from t1 LEFT OUTER JOIN t2 ON (t1.id = t2.id);
        ID         ID
         3          3
         4          4
         1
         2
-- RIGHT OUTER JOIN
SQL> select t1.id, t2.id
2 from t1 RIGHT OUTER JOIN t2 ON (t1.id = t2.id);
        ID         ID
         3          3
         4          4
                    6
                    5
-- LEFT JOIN (SAME AS LEFT OUTER JOIN)
SQL> ed
Wrote file afiedt.buf
1 select t1.id, t2.id
2* from t1 LEFT JOIN t2 ON (t1.id = t2.id)
SQL> /
        ID         ID
         3          3
         4          4
         1
         2
-- RIGHT JOIN (SAME AS RIGHT OUTER JOIN)
SQL> ed
Wrote file afiedt.buf
1 select t1.id, t2.id
2* from t1 RIGHT JOIN t2 ON (t1.id = t2.id)
SQL> /
        ID         ID
         3          3
         4          4
                    6
                    5
-- INNER JOIN (REGULAR JOIN)
SQL> ed
Wrote file afiedt.buf
1 select t1.id, t2.id
2* from t1 INNER JOIN t2 ON (t1.id = t2.id)
SQL> /
        ID         ID
         3          3
         4          4
-- FULL OUTER JOIN
SQL> ed
Wrote file afiedt.buf
1 select t1.id, t2.id
2* from t1 FULL OUTER JOIN t2 ON (t1.id = t2.id)
SQL> /
        ID         ID
         3          3
         4          4
         1
         2
                    6
                    5
6 rows selected.
SQL>

Why Inner join or Outer join is not used for Pool or Cluster tables ?

Hi SAP-ABAP Experts .
With Due Regards .
May u explain me why Inner join or Outer join is not useful for Pool or Cluster tables ?
because peoples advised not use Joins for Pool and Cluster tables , What harm will take place , If we do this ?
Best Regards to all : Rajneesh

Both Pooled and Cluster Tables are stored as tables within the database. Only the structures of the two table types which represent a single logical view of the data are defined within the ABAP/4 Data Dictionary. The data is actually stored in bulk storage in a different structure. These tables are commonly loaded into memory (i.e., 'buffered') due to the fact they are typically used for storing internal control information and other types of data with little or no external (business) relevance.
Pooled and cluster tables are usually used only by SAP and not used by customers, probably because of the proprietary format of these tables within the database and because of technical restrictions placed upon their use within ABAP/4 programs. On a pooled or cluster table:
Secondary indexes cannot be created.
You cannot use the ABAP/4 constructs select distinct or group by.
You cannot use native SQL.
You cannot specify field names after the order by clause. order by primary key is the only permitted variation.
I hope it helps.
Best Regards,
Vibha
Please mark all the helpful answers

Inner join Vs Outer join with ABAP code...?

Inner join Vs Outer join with ABAP code...?

Inner Join means, it will not select that recor at all, unless there is a matching entry in the second table.
suppose table VBAK INNER join table VBAP on VBAKVBELN = VBAPVBELN.
In this case, if there are no entries in VBAP, the header entry also will not show up.
But in case of OUTER JOIN, even if there is no items, it will show the header entry(VBAK) with blank columns for fields from item table.(VBAP)
here is one sample for inner join.
SELECT   A~EBELN
           A~EKORG
           A~EKGRP
           A~BSART
           A~LPONR
           A~LOEKZ
           A~LIFNR
           A~RESWK
           B~AEDAT
           B~WERKS
           B~MATNR
           B~MENGE
           B~EBELP
           B~ELIKZ
           B~PLIFZ
           B~PSTYP
           B~KNTTP
           B~MATKL
           B~ZZD_PLANT
           FROM EKKO AS A INNER JOIN EKPO AS B
           ON
           AEBELN = BEBELN
           INTO CORRESPONDING FIELDS OF TABLE T_DATA
           FOR ALL ENTRIES IN T_EKET
           WHERE
           A~EBELN EQ T_EKET-EBELN AND
           A~BSART EQ C_UBSTO      AND
           A~EKORG IN S_EKORG      AND
           A~EKGRP IN S_EKGRP      AND
           A~BSTYP EQ C_BSTYP      AND
           A~LOEKZ EQ SPACE        AND " Order not deleted
           A~RESWK IN S_RESWK      AND
           B~EBELN EQ T_EKET-EBELN AND
           B~EBELP EQ T_EKET-EBELP AND
           B~WERKS IN S_WERKS      AND
           B~MATNR IN S_MATNR      AND
           B~MATKL IN S_MATKL      AND
           B~LOEKZ EQ SPACE.           " Line item not deleted

Outer join/inner join

I have 4 related tables and want to join them all but can't
figure out how to do it. Here are the columns that need to join:
Table 1: EventID, PromoterID
Table 2: EventID, LeagueID
Table 3: LeagueID
Table 4: PromoterID
I want to join like this:
Table2.EventID *= Table1.EventID and
Table2.PromoterID = Table4.PromoterID and
Table2.LeagueID = Table3.LeagueID
But I can't do an outer and inner join on the same table.
Events can have multiple leagues related to it. If I use
inner joins for everything, it turns out okay until you search for
an event by League - if that happens and the event has more than
one related league, the search results will only show the league
searched by and not all the other related leagues. If you search by
other info like month or year, all leagues related to a particular
event show up in the search results for each event. When I try to
do an outer join on table 2 based on eventid, I then get stuck
trying to join table 2 and table 3.
This is probably a simple problem but my brain is feeling too
fried to figure it out - can anyone help? Thanks!!

You can also pull in the eventids based on leagues if your
SQL engine supports subqueries.
where
Table2.EventID = Table1.EventID and
Table2.PromoterID = Table4.PromoterID and
Table2.LeagueID = Table3.LeagueID
<cfif isdefined("form.leagueid")>
<cfif trim(form.leagueid) neq ''>
and table2.eventid in
(select t2a.eventid from table2 t2a
where t2a.eventid = table2.eventid
and t2a.leagueid = '#form.leagueid#')
</cfif>
</cfif>
<cfif isdefined("form.eventid")>
<cfif trim(form.eventid) neq ''>
and table2.eventid = '#form.eventid#'
</cfif>
</cfif>
<cfif isdefined("form.promoterid")>
<cfif trim(form.promoterid) neq ''>
and table2.prompterid = '#form.promoterid#'
</cfif>
</cfif>
...

How to do inner join ,outer join, left join ,right join by using infoset

how to do inner join ,outer join, left join ,right join by using infoset

Hi
If you want to make join ,outer join, left join ,right join then its possible if you are using ODS or direct infoobject (In BW3.5) and if you are using BI7.0 then you also make join ,outer join, left join ,right join with Cube also.
For making join ,outer join, left join ,right join in infosets you just select your info provider then right click on your infoarea from context menu select info set after doing this one pop-up opens here u define your infoset technical name and give either ODS object name of infoobject name.
After doing this next screen opens in right hand side your selectes ODS or infoobject shows in graphical format .
and left hand side it shows one menu bar here you can select another ODS or infoobject for making join ,outer join, left join ,right join .just click on ODS button in menu bar and select ODS drag your selected ODS from Left to right after doing this your selected ODS shown in right hand side window in graphical format you just now after doing this you are able to make join ,outer join, left join ,right join for this first you select field from one ods and drag a line from 1 ods to second ods after doing this one arrow is created from one ods to another ods just right click on arrow and make join ,outer join, left join ,right join in to your ODS.
I think its clear how we can we make join ,outer join, left join ,right join in infoset.If you have any further query then welcome.
Assign Points...............
Thanks and regards
Ankit modi

Mixed Inner and Outer Joins in One SQL

Oracle 11g.
There are four tables:
T1 (primary key: pk_t1)
T2 (primary key: pk_t2, foreign key fk_t2_ref_t1)
T3 (primary key: pk_t3, foreign key fk_t3_ref_t2)
T4 (primary key: pk_t4, foreign key fk_t4_ref_t3)
This is what I want to do: inner join among T1, T2, and T3, then outer join with T4 (T4 may contain the null rows). Something like:
procedure sp_test(
p_where_clause)
select *
from
     T1 inner joint T2 on pk_t1 = fk_t2_ref_t1
    inner joint T3 on pk_t2 = fk_t3_ref_t2
    left outer join T3 on pk_t3 = fk_t4_ref_t3
where p_where_clause;
OR
select *
from
     T4 right outer join T3 on pk_t3 = fk_t4_ref_t3
    inner joint T2 on pk_t2 = fk_t3_ref_t2
    inner joint T1 on pk_t1 = fk_t2_ref_t1
where p_where_clause;
Please help me to write a correct SQL to achieve this goal.
Thanks

Hi,
Whenever you have a problem, please post a little sample data (CREATE TABLE and INSERT statements, relevant columns only) from all tables involved, so that the people who want to help you can re-create the problem and test their ideas.
Also post the results you want from that data, and an explanation of how you get those results from that data, with specific examples.
Always say which version of Oracle you're using (for example, 11.2.0.2.0).
See the forum FAQ: https://forums.oracle.com/message/9362002
I'm guessing that your first attempt
select *
from
     T1 inner joint T2 on pk_t1 = fk_t2_ref_t1
    inner joint T3 on pk_t2 = fk_t3_ref_t2
    left outer join T3 on pk_t3 = fk_t4_ref_t3
where p_where_clause;
was close; only you want to include t4 rather than a second copy of t3, and you need to spell JOIN correctly:
SELECT *        -- You'll probably want to specify columns
FROM             t1
INNER JOIN       t2     ON pk_t1 = fk_t2_ref_t1
INNER JOIN       t3     ON pk_t2 = fk_t3_ref_t2
LEFT OUTER JOIN t4     ON pk_t3 = fk_t4_ref_t3
WHERE ...

Oute Join and Inner Join

Hi,
I need to join three tables, based on some conditions (EKPO, EKBE and EKKN Note: All PO line items from EKPO will have a movement associated in the EKBE Table. Capture all PO line items where no matches found in the EKPO-EKBE join)
for the above requirement shall I write my query like this?
SELECT ekpo~ebeln
         ekpo~ebelp
         ekpo~loekz
         ekpo~txz01
         ekpo~matnr
         ekpo~bukrs
         ekpo~werks
         ekpo~menge
         ekpo~meins
         ekpo~knttp
         ekbe~vgabe
         ekbe~bwart
         ekbe~menge
         ekbe~dmbtr
         ekbe~shkzg
         ekkn~sakto
         ekkn~kostl
         ekkn~ps_psp_pnr
INTO CORRESPONDING FIELDS OF TABLE i_podata
         FROM ekpo LEFT OUTER JOIN ekbe ON ekbeebeln = ekpoebeln AND
                                           ekbeebelp = ekpoebelp
                        INNER JOIN ekkn ON ekknebeln = ekpoebeln AND
                                           ekknebelp = ekpoebelp
                                     WHERE ekpo~werks IN s_werks AND
                                           ekpo~ebeln IN s_ebeln.
Shall I use both Outer Join and Inner join in one Query?
Please correcte me.
Thanks
Frank Rex

Hi,
You can use both inner join and outer join in the same select statement.
Ensure first all the inner joins between tables are declared and put the left outer join at the end.
Some sample code for your reference:
SELECT
          AVBELN AKUNNR ABSTNK ABSTDK AVKORG AVTWEG AAUART AKNUMV
          BPOSNR BMATNR BWERKS BSPART BLGORT BKZWI1
          SUM( BKWMENG ) AS KWMENG DBZIRK D~VKGRP
          EDISPO EPRCTR
FROM VBAK AS A INNER JOIN VBAP AS B ON AVBELN EQ BVBELN
               INNER JOIN VBPA AS C ON CVBELN EQ BVBELN
               INNER JOIN KNVV AS D ON DKUNNR EQ AKUNNR
            AND DVKORG EQ AVKORG AND DVTWEG EQ AVTWEG
               LEFT OUTER JOIN MARC AS E ON E~MATNR EQ
                         BMATNR AND EWERKS EQ B~WERKS
          INTO CORRESPONDING FIELDS OF TABLE IT_ORDERS
          WHERE A~VKORG IN SO_VKORG
          AND A~VTWEG IN SO_VTWEG
          AND A~KUNNR IN SO_KUNNR
          AND A~ERDAT IN SO_ERDAT
          AND A~AUART IN ('ZFOR','ZROR','ZEOR','ZDXR','ZXOR','ZRM1','ZGOR','ZSOR')
          AND B~MATNR IN SO_MATNR
          AND B~WERKS IN SO_WERKS
          AND B~SPART IN SO_SPART
          AND B~ABGRU EQ SPACE
          AND A~LIFSK EQ SPACE
          AND A~FAKSK EQ SPACE
          AND B~VSTEL IN SO_VSTEL
          AND B~LGORT IN SO_LGORT
          AND C~KUNNR IN SO_SHIP
          AND C~PARVW EQ 'WE'
          AND D~VKGRP IN SO_VKGRP
          AND D~BZIRK IN SO_BZIRK
          AND B~LGORT NE '0950'
          GROUP BY AVBELN AKUNNR ABSTNK ABSTDK
          AVKORG AVTWEG AAUART AKNUMV B~POSNR
          BMATNR BWERKS BSPART BKZWI1 D~BZIRK
          DVKGRP BLGORT EDISPO EPRCTR E~MATGR.
Lakshminarayanan.
P.S.Mark all helpful answers for points.

Performance difference between left outer join / inner join

Hi,
I've got a complex query which among other things accesses quite a large table. If I use inner join to join this table, the response is quite fast and execution plan shows it uses nested loops to gather the data.
If I change inner join to left outer join, I get a big performance drop. Cost of query goes from 1441 to 28544.
I don't uderstand why there's such a difference. For inner join, database has to remove all the rows that don't have match in inner-joined table. For left join it can keep all records and just return NULL values for records that don't have a match. In my mind left join should be faster, as it seems simpler. And the access plan could be the same, couldn't it?
Execution plan for inner join:
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 1 | 288 | 1441 (1)| 00:00:18 |
| 1 | HASH GROUP BY | | 1 | 288 | 1441 (1)| 00:00:18 |
| 2 | NESTED LOOPS OUTER | | 1 | 288 | 1440 (1)| 00:00:18 |
| 3 | NESTED LOOPS | | 1 | 261 | 1438 (1)| 00:00:18 |
| 4 | NESTED LOOPS | | 318 | 74412 | 508 (1)| 00:00:07 |
| 5 | NESTED LOOPS | | 318 | 51834 | 189 (0)| 00:00:03 |
| 6 | TABLE ACCESS BY INDEX ROWID| RESURCE | 1 | 106 | 1 (0)| 00:00:01 |
|* 7 | INDEX UNIQUE SCAN | RESURCE_PRINCIPAL_NAME_INDEX | 1 | | 0 (0)| 00:00:01 |
| 8 | TABLE ACCESS BY INDEX ROWID| TASK_USES_RESURCE | 318 | 18126 | 188 (0)| 00:00:03 |
|* 9 | INDEX RANGE SCAN | TASK_USES_RESUR_IDX$$_0CDC0002 | 318 | | 3 (0)| 00:00:01 |
| 10 | TABLE ACCESS BY INDEX ROWID | TASK | 1 | 71 | 1 (0)| 00:00:01 |
|* 11 | INDEX UNIQUE SCAN | TASK_PK | 1 | | 0 (0)| 00:00:01 |
| 12 | TABLE ACCESS BY INDEX ROWID | TASK_WORK_HISTORY | 1 | 27 | 3 (0)| 00:00:01 |
|* 13 | INDEX RANGE SCAN | TASK_WORK_HISTORY_INDEX1 | 1 | | 2 (0)| 00:00:01 |
| 14 | TABLE ACCESS BY INDEX ROWID | TASK_USES_RESURCE | 1 | 27 | 2 (0)| 00:00:01 |
|* 15 | INDEX UNIQUE SCAN | TASK_USES_RESURCE_UK1 | 1 | | 1 (0)| 00:00:01 |
For left outer join:
| Id | Operation | Name | Rows | Bytes |TempSpc| Cost (%CPU)| Time |
| 0 | SELECT STATEMENT | | 318 | 1596K| | 28544 (2)| 00:05:43 |
|* 1 | HASH JOIN OUTER | | 318 | 1596K| 1584K| 28544 (2)| 00:05:43 |
| 2 | VIEW | | 318 | 1580K| | 508 (1)| 00:00:07 |
| 3 | NESTED LOOPS | | 318 | 74412 | | 508 (1)| 00:00:07 |
| 4 | NESTED LOOPS | | 318 | 51834 | | 189 (0)| 00:00:03 |
| 5 | TABLE ACCESS BY INDEX ROWID| RESURCE | 1 | 106 | | 1 (0)| 00:00:01 |
|* 6 | INDEX UNIQUE SCAN | RESURCE_PRINCIPAL_NAME_INDEX | 1 | | | 0 (0)| 00:00:01 |
| 7 | TABLE ACCESS BY INDEX ROWID| TASK_USES_RESURCE | 318 | 18126 | | 188 (0)| 00:00:03 |
|* 8 | INDEX RANGE SCAN | TASK_USES_RESUR_IDX$$_0CDC0002 | 318 | | | 3 (0)| 00:00:01 |
| 9 | TABLE ACCESS BY INDEX ROWID | TASK | 1 | 71 | | 1 (0)| 00:00:01 |
|* 10 | INDEX UNIQUE SCAN | TASK_PK | 1 | | | 0 (0)| 00:00:01 |
| 11 | VIEW | | 1480K| 73M| | 23431 (2)| 00:04:42 |
|* 12 | HASH JOIN RIGHT OUTER | | 1480K| 76M| 38M| 23431 (2)| 00:04:42 |
| 13 | TABLE ACCESS FULL | TASK_USES_RESURCE | 1486K| 21M| | 2938 (2)| 00:00:36 |
| 14 | VIEW | | 1445K| 53M| | 15031 (2)| 00:03:01 |
| 15 | HASH GROUP BY | | 1445K| 37M| 110M| 15031 (2)| 00:03:01 |
| 16 | TABLE ACCESS FULL | TASK_WORK_HISTORY | 1445K| 37M| | 3897 (2)| 00:00:47 |
--------------------------------------------------------------------------------------------------------------------------

...continued
Complete execution plan for left join:
| Id | Operation                       | Name                           | Rows | Bytes |TempSpc| Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT                |                                |   318 | 1594K|       | 28544   (2)| 00:05:43 |
|* 1 | HASH JOIN OUTER                |                                |   318 | 1594K| 1584K| 28544   (2)| 00:05:43 |
|   2 |   VIEW                          |                                |   318 | 1578K|       |   508   (1)| 00:00:07 |
|   3 |    NESTED LOOPS                 |                                |   318 | 74412 |       |   508   (1)| 00:00:07 |
|   4 |     NESTED LOOPS                |                                |   318 | 51834 |       |   189   (0)| 00:00:03 |
|   5 |      TABLE ACCESS BY INDEX ROWID| RESURCE                        |     1 |   106 |       |     1   (0)| 00:00:01 |
|* 6 |       INDEX UNIQUE SCAN         | RESURCE_PRINCIPAL_NAME_INDEX   |     1 |       |       |     0   (0)| 00:00:01 |
|   7 |      TABLE ACCESS BY INDEX ROWID| TASK_USES_RESURCE              |   318 | 18126 |       |   188   (0)| 00:00:03 |
|* 8 |       INDEX RANGE SCAN          | TASK_USES_RESUR_IDX$$_0CDC0002 |   318 |       |       |     3   (0)| 00:00:01 |
|   9 |     TABLE ACCESS BY INDEX ROWID | TASK                           |     1 |    71 |       |     1   (0)| 00:00:01 |
|* 10 |      INDEX UNIQUE SCAN          | TASK_PK                        |     1 |       |       |     0   (0)| 00:00:01 |
| 11 |   VIEW                          |                                | 1480K|    73M|       | 23431   (2)| 00:04:42 |
|* 12 |    HASH JOIN RIGHT OUTER        |                                | 1480K|    76M|    38M| 23431   (2)| 00:04:42 |
| 13 |     TABLE ACCESS FULL           | TASK_USES_RESURCE              | 1486K|    21M|       | 2938   (2)| 00:00:36 |
| 14 |     VIEW                        |                                | 1445K|    53M|       | 15031   (2)| 00:03:01 |
| 15 |      HASH GROUP BY              |                                | 1445K|    37M|   110M| 15031   (2)| 00:03:01 |
| 16 |       TABLE ACCESS FULL         | TASK_WORK_HISTORY              | 1445K|    37M|       | 3897   (2)| 00:00:47 |
Query Block Name / Object Alias (identified by operation id):
   1 - SEL$1AFB0324
   2 - SEL$58A6D7F6 / from$_subquery$_005@SEL$8
   3 - SEL$58A6D7F6
   5 - SEL$58A6D7F6 / RESURCEWORKER@SEL$2
   6 - SEL$58A6D7F6 / RESURCEWORKER@SEL$2
   7 - SEL$58A6D7F6 / TASKUSESRESURCE@SEL$1
   8 - SEL$58A6D7F6 / TASKUSESRESURCE@SEL$1
   9 - SEL$58A6D7F6 / TASK@SEL$1
10 - SEL$58A6D7F6 / TASK@SEL$1
11 - SEL$7EBCC247 / TRW@SEL$3
12 - SEL$7EBCC247
13 - SEL$7EBCC247 / TUR@SEL$4
14 - SEL$6        / TRW_IN@SEL$5
15 - SEL$6
16 - SEL$6        / TWH@SEL$6
Predicate Information (identified by operation id):
   1 - access("TRW"."RESURCE_ID"(+)="TASKUSESRESURCE"."RESURCE_ID" AND "TRW"."TASK_ID"(+)="TASK"."ID")
   6 - access("RESURCEWORKER"."USER_PRINCIPAL_NAME"=U'jernej')
   8 - access("TASKUSESRESURCE"."RESURCE_ID"="RESURCEWORKER"."ID")
10 - access("TASKUSESRESURCE"."TASK_ID"="TASK"."ID")
12 - access("TUR"."RESURCE_ID"(+)="TRW_IN"."RESURCE_ID" AND "TUR"."TASK_ID"(+)="TRW_IN"."TASK_ID")                                                                                                                                                                                                         Jonathan, I've been to one of your workshops in Ljubljana. I'm still trying to understand everything you explained and use it, but there's much I have to learn and understand.
The way I see this query it should fist join and filter the first three tables and only then join the trw subquery. The problem with this subqrey is task_work_history table, which is accessed in very different ways in different places, so there will always be many reads to gather required data. For now, however, I'd be hapy to just bring the performance of inner join to left join...

Inner Selects vs. Outer Joins

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