Self Join

Hi All,
I have following table which has reciprocal records as well as non reciprocal such as relid = 3. How can I find the record with relid = 3?
relid
relrelatid
whois
whose
1
10
emp
mngr
10
1
mngr
emp
2
20
emp
mngr
20
2
mngr
emp
3
30
emp
mngr
Thanks in advance.

Please post DDL, so that people do not have to guess what the keys, constraints, Declarative Referential Integrity, data types, etc. in your schema are. Learn how to follow ISO-11179 data element naming conventions and formatting rules. Temporal data should
use ISO-8601 formats. Code should be in Standard SQL as much as possible and not local dialect.
This is minimal polite behavior on SQL forums. You do not know that rows are not records! Would you please explain what a “reciprocal row” is? I never heard this term before. And I have some credentials in SQL and RDBMS.
Without any help from you, I will guess this means there is a symmetric relation in the data model: (a R b)  (b R a)
--CELKO-- Books in Celko Series for Morgan-Kaufmann Publishing: Analytics and OLAP in SQL / Data and Databases: Concepts in Practice Data / Measurements and Standards in SQL SQL for Smarties / SQL Programming Style / SQL Puzzles and Answers / Thinking
in Sets / Trees and Hierarchies in SQL

Similar Messages

Self join with fact table in Obie 10G

I am a newbie to obiee.I have a development requirement as follows-
I need to find supervisors designation with the existing star RPD design. explanation is below
                                                    DIM_Designation(Desig_Wid)
                                                  |(Row_wid)
                                                  |
DIM_EMPLOYEE--------WORKER_FACT------------DIM_Supervisor
(Row_Wid)-----------------(Employee_Wid)
                                  (Supervisor_Wid)------------(Row_Wid)
3 dimension is joined to fact to get employee, his supervisor and designation of employee. now i want to get the supervisor's designation? how is it possible? already employee and supervisor dimension is same W_employee_d table joined with fact as alias DIM_EMPLOYEE and DIM_SUPERVISOR. how to do self join with fact to get supervisor's designation. i do not have any supervisor_desig_wid in fact table. any help is deeply appreciated.

Yes,Duplicate the fact table create a primary key on the newly fact table alias dimension table.So you can ur data modelling as usual.

How to achieve parent-child relationship using self join?

my table structure is as follows
parent child name
-1     1     A1
1     2     A2
1     3     A3
how to achieve the hierarchy model using self join. this can be easily achieved using "connect by prior". but how to achieve the same using self join?

Hi,
Yes, that's definitely possible. If you only need to display two levels from the hierarchy, a self-join is a good option. Make it an outer join if you need to show everyone on one level, regardless of whether they have a match on the other level or not; for example, if you want the output:
child_name     child_id     parent_name     parent_id
A1          1
A2          2          A1          1
A3          3          A1          1It's good that you posted some sample data. Now post the results you want from that data, and your query (what you think is the best attempt you've made so far). If you haven't tried anything so far, then look at some other simple self-join to get ideas.

Problem writing a XSLT to convert XML in desired format from a table having self join

Hello,
I have to write a style sheet to convert XML generated from XSQL into a different format. The query that I have is as follows.
select LEVEL depth,
'H' || hierarchy_id id,
name,
nvl2(parent_id, 'H' || parent_id, 0) parent_id,
CURSOR(select LEVEL depth,
'H' || hierarchy_id hid,
name hname,
nvl2(parent_id, 'H' || parent_id, 0) hparent_id,
decode(system_id, NULL, '0', 'S' || system_id) formatted_system_id,
system_id
from hierarchy
where parent_id = h.hierarchy_id
and system_id is not null
) as systems
from hierarchy h
where system_id is null
start with parent_id is null
connect by prior hierarchy_id = parent_id
The hierarchy table has a self join to itself. The selfjoin is on the hierarchyid and the parentid fields which is evident from the query.
Here the hierarchy table contains the parent system and also the child systems underneath. The problem is that the no. of levels that it can go deep is not fixed. The output of this in sqlplus is as follows.
Depth Hierarchyid, name parentid
1 h1 xxx <null>
2 h2 bbb h1
3 h3 ccc h2
<Cursor for systems>
hid hname hparentid formatted_system_id systemid
h4 ccc h2 s1 1
h5 ccc h2 s2 2
<Back to original data>
Depth Hierarchyid, name parentid
2 h6 ddd h1
2 h7 eee h1
The desired output required from the stylesheet is as follows
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1>
<h id=h3 name=ccc parentid=h2>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
Could some one guide me as to how to get this. I did write a stylesheet which gives me the following output.
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1/>
<h id=h3 name=ccc parentid=h2/>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
As you can see I am missing the closing of the tag on the 7th line in the desired format. I have written the following stylesheet.

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>

<xsl:template match="HIERARCHY">
<HIERARCHY><xsl:apply-templates/></HIERARCHY>
</xsl:template>

<xsl:template match="HELEMENT">
<xsl:choose>
<xsl:when test="PARENT_ID=0">
<helement id="{ID}" name="{NAME}" parentid="{PARENT_ID}"/>
</xsl:when>
<xsl:when test="PARENT_ID!='0'">
<helement2 id="{ID}" name="{NAME}" parentid="{PARENT_ID}">
<xsl:for-each select="SYSTEMS/SYSTEMS_ROW">
<helement3 id="{HID}" name="{HNAME}" parentid="{HPARENT_ID}" systemid="{FORMATTED_SYSTEM_ID}">
</helement3>
</xsl:for-each>
</helement2>
</xsl:when>
<xsl:otherwise>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
Is there any way of achieving this. Any help would be appreciated. I am using XSQL to generate first the basic XML output and then applying stylesheet to achieve the desired output.
Sincerely,
D

Hello,
I have to write a style sheet to convert XML generated from XSQL into a different format. The query that I have is as follows.
select LEVEL depth,
'H' || hierarchy_id id,
name,
nvl2(parent_id, 'H' || parent_id, 0) parent_id,
CURSOR(select LEVEL depth,
'H' || hierarchy_id hid,
name hname,
nvl2(parent_id, 'H' || parent_id, 0) hparent_id,
decode(system_id, NULL, '0', 'S' || system_id) formatted_system_id,
system_id
from hierarchy
where parent_id = h.hierarchy_id
and system_id is not null
) as systems
from hierarchy h
where system_id is null
start with parent_id is null
connect by prior hierarchy_id = parent_id
The hierarchy table has a self join to itself. The selfjoin is on the hierarchyid and the parentid fields which is evident from the query.
Here the hierarchy table contains the parent system and also the child systems underneath. The problem is that the no. of levels that it can go deep is not fixed. The output of this in sqlplus is as follows.
Depth Hierarchyid, name parentid
1 h1 xxx <null>
2 h2 bbb h1
3 h3 ccc h2
<Cursor for systems>
hid hname hparentid formatted_system_id systemid
h4 ccc h2 s1 1
h5 ccc h2 s2 2
<Back to original data>
Depth Hierarchyid, name parentid
2 h6 ddd h1
2 h7 eee h1
The desired output required from the stylesheet is as follows
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1>
<h id=h3 name=ccc parentid=h2>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
Could some one guide me as to how to get this. I did write a stylesheet which gives me the following output.
<h id=h1 name=xxx>
<h id=h2 name=bbb parentid=h1/>
<h id=h3 name=ccc parentid=h2/>
<h id=h4 name=fff parentid=h3 systemid=s1>
<h id=h5 name=ggg parentid=h3 systemid=s2>
</h>
<h id=h6 name=ddd parentid=h1/>
<h id=h7 name=eee parentid=h1/>
</h>
As you can see I am missing the closing of the tag on the 7th line in the desired format. I have written the following stylesheet.

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="@*|node()"/>
</xsl:copy>
</xsl:template>

<xsl:template match="HIERARCHY">
<HIERARCHY><xsl:apply-templates/></HIERARCHY>
</xsl:template>

<xsl:template match="HELEMENT">
<xsl:choose>
<xsl:when test="PARENT_ID=0">
<helement id="{ID}" name="{NAME}" parentid="{PARENT_ID}"/>
</xsl:when>
<xsl:when test="PARENT_ID!='0'">
<helement2 id="{ID}" name="{NAME}" parentid="{PARENT_ID}">
<xsl:for-each select="SYSTEMS/SYSTEMS_ROW">
<helement3 id="{HID}" name="{HNAME}" parentid="{HPARENT_ID}" systemid="{FORMATTED_SYSTEM_ID}">
</helement3>
</xsl:for-each>
</helement2>
</xsl:when>
<xsl:otherwise>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
Is there any way of achieving this. Any help would be appreciated. I am using XSQL to generate first the basic XML output and then applying stylesheet to achieve the desired output.
Sincerely,
D

Oracle query with out using self join

hi friends,
i have one table for exeample PERSTATUS
pk/fK STUDENT NUMBER SUBJECT MARKS STATUS
1 ACCOUNTS 15 RED
1 MATHS 35 YELLOW
1 SCINECE 45 GREEN
2 ACCOUNTS 55 BROWN
2 MATHS 35 YELLOW
2 SCINECE 45 GREEN
3 ACCOUNTS 15 RED
3 MATHS 35 YELLOW
3 SCINECE 45 GREEN
i want students how status is both red and yellow so i am using self join
i want students status is both red and yellow so i am using self join
SELECT PS.STUDENTNUMBER,PS.STATUS,PS.STATUS1 FROM PERSTATUS PS ,PERSTATUS PS1
WHERE PS.STUDENTNUMBER-PS1.STUDENTNUMER
PS.STATUS='RED' AND PS1.STAUTS='YELLOW'
i want students status is both RD and YELLOW AND GREEN so i am using self join( two self joinS}
SELECT PS.STUDENTNUMBER,PS.STATUS,PS.STATUS,PS2.STATUS FROM PERSTATUS PS ,PERSTATUS PS1,PERSTATUS PS2
WHERE PS.STUDENTNUMBER-PS1.STUDENTNUMER AND PS.STUDENTNUMBER-PS2.STUDENTNUMBER
PS.STATUS='RED' AND PS1.STAUTS='YELLOW' AND PS2.STAUTUS='GREEN'
if i require MORE STATUS then more self joins required, is there any alternative to achive this
and if results comes in multiple rows are accepted (since with the above query result will come in single row)
i tried to use group by (studentnumber,status) with status='red' and status='yellow'
but it is not possible could you povidet he solution

Hi,
Whenever you have a problem, please post CREATE TABLE and INSERT statements for your sample data, and the exact results you want from that data. Explain how you get those results from that data.
See the forum FAQ {message:id=9360002}
Here's an example of how to post the sample data:
CREATE TABLE     perstatus
(       studentnumber     NUMBER
,     subject          VARCHAR2 (10)
,     marks          NUMBER
,     status          VARCHAR2 (10)
INSERT INTO perstatus (studentnumber, subject,    marks, status)
       VALUES           (1,           'ACCOUNTS', 15,       'RED');
INSERT INTO perstatus (studentnumber, subject , marks, status)
       VALUES           (1,           'MATHS',        35,       'YELLOW');
INSERT INTO perstatus (studentnumber, subject,    marks, status)
       VALUES           (1,           'SCINECE', 45,       'GREEN');
INSERT INTO perstatus (studentnumber, subject,    marks, status)
       VALUES           (2,           'ACCOUNTS', 55,       'BROWN');
INSERT INTO perstatus (studentnumber, subject , marks, status)
       VALUES           (2,           'MATHS',        35,       'YELLOW');
INSERT INTO perstatus (studentnumber, subject,    marks, status)
       VALUES           (2,           'SCINECE', 45,       'GREEN');
INSERT INTO perstatus (studentnumber, subject,    marks, status)
       VALUES           (3,           'ACCOUNTS', 15,       'RED');
INSERT INTO perstatus (studentnumber, subject , marks, status)
       VALUES           (3,           'MATHS',        35,       'YELLOW');
INSERT INTO perstatus (studentnumber, subject,    marks, status)
       VALUES           (3,           'SCINECE', 45,       'GREEN');You were on the right track, thinking about GROUP BY. You're interested in something about the whole group of rows that has the same studentnumber. Looking at any individual row won't tell you if that row is part of the group you're interested in or not.
If you want to see information about the group as a whole, you can do the whole job with GROUP BY. In this case, studnetnumber is the only thing that an entire group has in common. If you wanted to see the studentnumbers that had both RED and YELLOW, that is:
STUDENTNUMBER
            1
            3here's one way you could do it:
SELECT       studentnumber
FROM       perstatus
WHERE       status     IN ('RED', 'YELLOW')
GROUP BY studentnumber
HAVING       COUNT (DISTINCT status) = 2 -- That is, both RED and YELLOW
ORDER BY studentnumber
;But say you wanted to see details about individuals in the group; for example, say we want to see all the columns for students that have all 3 of RED, YELLOW and GREEN, like this:
STUDENTNUMBER SUBJECT         MARKS STATUS
            1 SCINECE            45 GREEN
            1 ACCOUNTS           15 RED
            1 MATHS              35 YELLOW
            3 SCINECE            45 GREEN
            3 ACCOUNTS           15 RED
            3 MATHS              35 YELLOWWe used the aggregate COUNT function earlier, but aggregate functions require collapsing the results down to one row per group.
However, most of the aggregate functions, like COUNT, have analytic counterparts, that can give the same results without collapsing the result set. Here's one way to get the results above, using the analytic COUNT function:
WITH     got_cnt          AS
     SELECT studentnumber, subject, marks, status
     ,     COUNT ( DISTINCT CASE
                               WHEN status IN ('RED', 'YELLOW', 'GREEN')
                         THEN status
                           END
                ) OVER (PARTITION BY studentnumber)     AS cnt
     FROM    perstatus
SELECT    studentnumber, subject, marks, status
FROM       got_cnt
WHERE       cnt = 3
ORDER BY studentnumber
,            status
;

Oracle doc inconsistent on materialize view with union all and self joins

First of all, I can't seem to create a materialized view containing self-joins AND union all. Is it possible?
I checked Oracle 9i (my version: PL/SQL Release 9.2.0.4.0 - Production) documentation and I get different answers (or so it seems to me).
First I saw this: "The COMPATIBILITY parameter must be set to 9.0 if the materialized aggregate view has inline views, outer joins, self joins or grouping sets and FAST REFRESH is specified during creation..."
Did you see the part about 'self joins' in there? I did and I was pumped because that seems to say that you CAN have 'self joins' (and my compatibility is 9.2...)
BUT
In the very same document I also found "Oracle does not allow self-joins in materialized join views." (rage)
You can see the document I am speaking of here: http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96520/mv.htm#574889
Whenever I try to create the mview I get the following error. (
In any caseORA-01446 cannot select ROWID from view with DISTINCT, GROUP BY, etc.

First of all, I can't seem to create a materialized view containing self-joins AND union all. Is it possible?
I checked Oracle 9i (my version: PL/SQL Release 9.2.0.4.0 - Production) documentation and I get different answers (or so it seems to me).
First I saw this: "The COMPATIBILITY parameter must be set to 9.0 if the materialized aggregate view has inline views, outer joins, self joins or grouping sets and FAST REFRESH is specified during creation..."
Did you see the part about 'self joins' in there? I did and I was pumped because that seems to say that you CAN have 'self joins' (and my compatibility is 9.2...)
BUT
In the very same document I also found "Oracle does not allow self-joins in materialized join views." (rage)
You can see the document I am speaking of here: http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96520/mv.htm#574889
Whenever I try to create the mview I get the following error. (
In any caseORA-01446 cannot select ROWID from view with DISTINCT, GROUP BY, etc.

How to resolve Self Joins in OBIEE

Hi All
Could any one help how to resolve the Self Join relations in OBIEE (ex. "SCOTT.EMP" table has "EMPNO" column which is referenced by "MGR" column in the same table.
Request:
Need to drill down from the Top manager to his employees and so on
Another example can be applied for reporting the Organisation Chart

This is a great article that shows ho to do the Alias:
Adding an Alias table within the BI physical layer using Oracle BI Administration Tool
http://www.mandsconsulting.com/adding-an-alias-table-within-oracle-bi-administration-tool
Thanks
Subra

Need help with self join query

Hello,
I have table A with the following data
oid parent_oid
10 4
4 2
2 2
12 6
6 6
parent_oid is the parent of oid. I'd like a query that shows the final parent of the oid. The result should show the following
oid final parent
10 2
4 2
2 2
12 6
6 6
I'm using Oracle 10g. I'm familiar with self joins, but that alone will not do the job. Thanks!

Hi,
arizona9952 wrote:
... I'm familiar with self joins, but that alone will not do the job.You're absolutely right!
A 2-way self join would work for rows have no parent, or rows that are directly connected to their final ancestor (such as oid=4), but not for anything farther away.
A 3-way self-join would work for one more level away from the final row, but no more. That would be enough for the small set of sample data that you posted, but it would not work if you added a new row with parent_id=10.
An N-way self-join would work for up to N+1 levels, but no more.
You need something that can go any number of levels, such as CONNECT BY:
SELECT     CONNECT_BY_ROOT oid     AS oid
,     parent_oid          AS final_parent
FROM     a
WHERE     CONNECT_BY_ISLEAF     = 1
CONNECT BY     oid     = PRIOR parent_oid
     AND     oid     != parent_oid
;Edited by: Frank Kulash on Feb 22, 2010 7:09 PM
Upon sober reflection, I think that a Top-Down query, like the one below, would be more efficient than a Bottom-Up query, like the one above:
SELECT     oid
,     CONNECT_BY_ROOT     parent_oid     AS final_parent
FROM     a
START WITH     parent_oid     = oid
CONNECT BY     parent_oid     = PRIOR oid
     AND     oid          != PRIOR oid
;

Student learning, self join

Our teacher isnt very clear on self joins, and searching brings up too complicated of info for someone like myself just learning, so i was hoping you guys could help out. Table below:
SQL> select * from grade;
STD_CODE GR_LNAME GR_FNAME GR_T1 GR_T2 GR_HW GR_PR
S1 Jordan Michael 95 80 98 90
S2 Barkley Charles 60 100 100 60
S3 Johnson Magic 88 98 96 98
S4 Williams Serena 92 92 92 92
S5 Duncan Tim 94 90 94 96
S6 Graff Steffi 85 84 83 72
S7 Navratilova Martina 91 88 94 95
Need to solve this question:
Create a view that will display names of students that have identical average grade (average of gr_t1, t2, hw, and pr)
I learned that we needed to create a self join to sniff out the averages that were the same.
I am pretty clueless on the logic of self join, but I made an attempt:
CREATE VIEW SAME_GRADES2 AS SELECT S.STD_FNAME, S.STD_LNAME, (GR_T1+GR_T2+GR_HW+GR_PR)/4 AVG_GR
FROM GRADE S, GRADE G
WHERE S.AVG_GR=G.AVG_GR;
i get an error on this: ORA-00904: "G"."AVG_GR": invalid identifier
No idea. Any help for a newbie?

sorry that last one was a syntax error... here is the result (obviously not what i need)
GR_FNAME GR_LNAME AVG_GR
Michael________Jordan____________90.75
Charles________Barkley____________80
Magic________Johnson____________95
Martina________Navratilova_________92
Serena________Williams____________92
Tim________Duncan______________93.5
Steffi________Graff _______________81
Martina________Navratilova _________92
Serena________Williams____________92
9 rows selected.
code:
CREATE VIEW SAME_GRADES2 AS SELECT S.GR_FNAME, S.GR_LNAME, (S.GR_T1+S.GR_T2+S.GR_HW+S.GR_PR)/4 AVG_GR
FROM GRADE S, GRADE G GROUP BY S.GR_FNAME
WHERE (S.GR_T1+S.GR_T2+S.GR_HW+S.GR_PR)/4 = (G.GR_T1+G.GR_T2+G.GR_HW+G.GR_PR)/4;
Edited by: user10188205 on Oct 22, 2008 4:42 PM

How to re-write this self join update using a CTE

I would like to improve my performance on this update statement and would like to try re-writing using a CTE:
UPDATE "usr_sessions" "a" SET "is_ended_at_trustable" = 't'
WHERE (
EXISTS (
SELECT 1
FROM "usr_sessions" "b"
WHERE "a"."ended_at" = "b"."started_at"
AND "a"."usr_space_id" = "b"."usr_space_id"
AND "a"."account_id" = "b"."account_id"
) ) AND "a"."is_ended_at_trustable" IS NULL
Any help is greatly appreciated! Open to other suggestions as well if there is a better way!

If I understood your description correctly, here's a way to accomplish the same thing, while dodging the need for the self join. The update itself won't be any faster, but the overall query leading to the update will likely be faster sans self-join.
(If my interpretation wasn't exactly what you meant, tweak the "partition by" clause).
MERGE is generally considered better then UPDATE, but your particular update isn't at risk for the shortcomings of update (still, Merge is newer, cooler, and more trustworthy).
Setup_Example_Data:
Declare @Usr_Sessions table (account_id int, usr_space_id int, is_ended_at_Trustable Char(1), started_at varchar(99), ended_at varchar(99))
Insert @Usr_Sessions
Select 1, 10, 't', 'A1', 'A1'
UNION ALL Select 2, 20, 'f', 'B1', 'B2'
UNION ALL Select 3, 30, NULL, 'C1', 'C1'
UNION ALL Select 4, 40, NULL, 'D1', 'D2'
UNION ALL Select 5, 50, NULL, 'E1', 'E2'
UNION ALL Select 5, 51, NULL, 'E3', 'E3'
UNION ALL Select 6, 61, NULL, 'F1', 'F2'
UNION ALL Select 6, 62, 't', 'F3', 'F3'
UNION ALL Select 6, 62, 'f', 'F4', 'F4'
Select 'Before', * from @Usr_Sessions
OP_Query:
BEGIN TRAN
UPDATE A SET is_ended_at_trustable = 't' from @usr_Sessions A-- Select * from @Usr_Sessions "a" --
WHERE (
EXISTS (
SELECT 1
FROM @usr_sessions "b"
WHERE "a"."ended_at" = "b"."started_at"
AND "a"."usr_space_id" = "b"."usr_space_id"
AND "a"."account_id" = "b"."account_id"
) ) AND "a"."is_ended_at_trustable" IS NULL
Select 'After 1', * from @Usr_Sessions
ROLLBACK TRAN /* Just to reset test data to original form, so second query below runs against original data */
Dodge_Self_Join:
With X as
Select *
, count(case when started_at = ended_at and is_ended_at_trustable is null then 'x' else null end)
over(partition by account_id, usr_space_id) as Updatable
From @Usr_Sessions
Update X
set is_ended_at_Trustable = 'T'
where Updatable > 0 -- EDIT -- fixed error, previously said "updatable = 1"
Select 'After 2', * from @Usr_Sessions

Self join using ABAP Query

Hello all,
How to create a self join using ABAP Query?
Say, I have this table EKBE with belnr (materials doc num) and lfbnr (reference material doc num). I have to pick the PO's from EKBE whose belnr doesnt have any lfbnr.
Regards
Madhumathi A

hi madhu,
tables : ekbe.
data itab like standard table of ekbe with header line.
select * from ekbe into table itab where belnr >< 0 and lfbnr = ' '.
loop at itab.
write :/ itab-belnr,itab-lfbnr.
endloop.
check this code this works to select the orders whose belnr doesnt have any lfbnr
reward points if useful.

How to write self join in sql?

Hi,
I have table named "table_upload", column "record_type" value "01,03,04....." and start_date,end_date and so on
And i will have value for start_date,end_date only for record_type=01,rest of type these two columns will be null.
now i need to write query with self join, to include above concept. can any one please help me .
and my query look like follows,

I just want to re write
Please provide DDL+DML + expected output!
and short explanation what is it that we all ask you for:
DDL = Data Definition Language. In our case that is, CREATE TABLE statements for your tables and other definitions that are needed to understand your tables structure and there for let us to test and reproduce the problem in our server. Without DDL no one
can execute any query.
How to get DDL: Right click on the table in Object Explorer and select script table as CREATE. Post these create table scripts here.
DML = data manipulation language is a family of queries used for manipulating the data it self like: inserting, deleting and updating data. In our case we need some sample data in order to check the query and get result, so we need some indert query for
sample data.
If you post a "create table query" for the tables and "insert <table> query" with some sample, then we could help you without Assuming/Guessing. There is a reason that DDL is generally asked for and expected when discussing query problems - it helps
to identify issues, clarify terminology and prevent incorrect assumptions. Sample data also provides a common point of reference for the discussion. A script that can be used to illustrate or reproduce the issue you have, will encourage others to help.
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ADF Tree with Self Join

Hi,
I want to make an application using component tree with one table. This table has menu_id and menu_parent.
I got a little problem when I use self joining table, it shown all parents and children.
I want only the root folder (parent) to be shown first and then by opening the menu_parent, i should be able to see the menu_id folders.
Can you please help me.
Thanks

Hi,
you need to have a viewcriteria in your vo for selecting the parents one, then while selecting vo in datacontrols in AM you need to select your viewcriteria in your vo by editing it.
Also you need to have a ViewLink between same viewobjects i.e menu_id->parent->id.
See if this helps.
Regards,
Santosh,

Self join in the HR schema

I'm a beginner going though a tutorial on joins using the HR schema:
an example of a self join was given as:
SELECT e.last_name AS Employee, m.last_name AS Manager
FROM employees e INNER JOIN employees m
ON (e.manager_id = m.employee_id);
this executes correctly, giving a column of Employee's name and their manager's name . However, I'm having trouble wrapping my head around the ON clause in this statement.
For example if I change the ON clause so that the statement is:
SELECT e.last_name AS Employee, m.last_name AS Manager
FROM employees e INNER JOIN employees m
ON (m.manager_id = e.employee_id);
I no longer get the correct answer but I'm not sure why?

You are getting different result because:
993451 wrote:
I'm a beginner going though a tutorial on joins using the HR schema:
an example of a self join was given as:
SELECT e.last_name AS Employee, m.last_name AS Manager
FROM employees e INNER JOIN employees m
ON (e.manager_id = m.employee_id);
earlier you were joining employee's manager_id with manager's employee_id.
this executes correctly, giving a column of Employee's name and their manager's name . However, I'm having trouble wrapping my head around the ON clause in this statement.
For example if I change the ON clause so that the statement is:
SELECT e.last_name AS Employee, m.last_name AS Manager
FROM employees e INNER JOIN employees m
ON (m.manager_id = e.employee_id);
now you are joining manager's manager_id with employee's employee_id
I no longer get the correct answer but I'm not sure why?
Now, can you make out the difference between the logic you are applying.
Regards,
Ankit Rathi
http://oraclenbeyond.blogspot.in

Recursive Self Join

Hi. I need to query the database of a document management system.   Documents are logically stored in folders in a tree structure and may be nested to arbitrary depth. The FOLDER table lists the names and metadata of folders.
Ultimately, I want to join the FOLDER table ("f") to the DOCUMENT table ("d") to get a list of documents by folder. The main thing I need help with is to build folder paths. I don't necessarily even
need to build full paths. I would be happy just listing all the individual folders under the root, and the documents they contain. I imagine to build folder paths involves a self join, but I don't know how to hadle arbitrary depth
The first two columns of the FOLDER table are FOLDER_ID and PARENT_FOLDER_ID. The data looks like this (where FOLDER_ID 1 represents the root folder):
FOLDER_ID     PARENT_FOLDER_ID
1                    null
2                    1
3                    1
4                    1
5                    2
6                    2
7                    1
etc.
Thanks for your help!

See Itzik Ben-Gan examples dealing with such queries.
CREATE TABLE Employees
empid int NOT NULL,
mgrid int NULL,
empname varchar(25) NOT NULL,
salary money NOT NULL,
CONSTRAINT PK_Employees PRIMARY KEY(empid),
CONSTRAINT FK_Employees_mgrid_empid
FOREIGN KEY(mgrid)
REFERENCES Employees(empid)
CREATE INDEX idx_nci_mgrid ON Employees(mgrid)
SET NOCOUNT ON
INSERT INTO Employees VALUES(1 , NULL, 'Nancy' , $10000.00)
INSERT INTO Employees VALUES(2 , 1 , 'Andrew' , $5000.00)
INSERT INTO Employees VALUES(3 , 1 , 'Janet' , $5000.00)
INSERT INTO Employees VALUES(4 , 1 , 'Margaret', $5000.00)
INSERT INTO Employees VALUES(5 , 2 , 'Steven' , $2500.00)
INSERT INTO Employees VALUES(6 , 2 , 'Michael' , $2500.00)
INSERT INTO Employees VALUES(7 , 3 , 'Robert' , $2500.00)
INSERT INTO Employees VALUES(8 , 3 , 'Laura' , $2500.00)
INSERT INTO Employees VALUES(9 , 3 , 'Ann' , $2500.00)
INSERT INTO Employees VALUES(10, 4 , 'Ina' , $2500.00)
INSERT INTO Employees VALUES(11, 7 , 'David' , $2000.00)
INSERT INTO Employees VALUES(12, 7 , 'Ron' , $2000.00)
INSERT INTO Employees VALUES(13, 7 , 'Dan' , $2000.00)
INSERT INTO Employees VALUES(14, 11 , 'James' , $1500.00)
The first request is probably the most common one:
returning an employee (for example, Robert whose empid=7)
and his/her subordinates in all levels.
The following CTE provides a solution to this request:
WITH EmpCTE(empid, empname, mgrid, lvl)
AS
-- Anchor Member (AM)
SELECT empid, empname, mgrid, 0
FROM Employees
WHERE empid = 7
UNION ALL
-- Recursive Member (RM)
SELECT E.empid, E.empname, E.mgrid, M.lvl+1
FROM Employees AS E
JOIN EmpCTE AS M
ON E.mgrid = M.empid
SELECT * FROM EmpCTE
Using this level counter you can limit the number of iterations
in the recursion. For example, the following CTE is used to return
all employees who are two levels below Janet:
WITH EmpCTEJanet(empid, empname, mgrid, lvl)
AS
SELECT empid, empname, mgrid, 0
FROM Employees
WHERE empid = 3
UNION ALL
SELECT E.empid, E.empname, E.mgrid, M.lvl+1
FROM Employees as E
JOIN EmpCTEJanet as M
ON E.mgrid = M.empid
WHERE lvl < 2
SELECT empid, empname
FROM EmpCTEJanet
WHERE lvl = 2
As mentioned earlier, CTEs can refer to
local variables that are defined within the same batch.
For example, to make the query more generic, you can use
variables instead of constants for employee ID and level:
DECLARE @empid AS INT, @lvl AS INT
SET @empid = 3 -- Janet
SET @lvl = 2 -- two levels
WITH EmpCTE(empid, empname, mgrid, lvl)
AS
SELECT empid, empname, mgrid, 0
FROM Employees
WHERE empid = @empid
UNION ALL
SELECT E.empid, E.empname, E.mgrid, M.lvl+1
FROM Employees as E
JOIN EmpCTE as M
ON E.mgrid = M.empid
WHERE lvl < @lvl
SELECT empid, empname
FROM EmpCTE
WHERE lvl = @lvl
Results generated thus far might be returned (but are not guaranteed to be),
and error 530 is generated. You might think of using the MAXRECURSION option
to implement the request to return employees who are two levels below
Janet using the MAXRECURSION hint instead of the filter in the recursive member
WITH EmpCTE(empid, empname, mgrid, lvl)
AS
SELECT empid, empname, mgrid, 0
FROM Employees
WHERE empid = 1
UNION ALL
SELECT E.empid, E.empname, E.mgrid, M.lvl+1
FROM Employees as E
JOIN EmpCTE as M
ON E.mgrid = M.empid
SELECT * FROM EmpCTE
OPTION (MAXRECURSION 2)
WITH EmpCTE(empid, empname, mgrid, lvl, sortcol)
AS
SELECT empid, empname, mgrid, 0,
CAST(empid AS VARBINARY(900))
FROM Employees
WHERE empid = 1
UNION ALL
SELECT E.empid, E.empname, E.mgrid, M.lvl+1,
CAST(sortcol + CAST(E.empid AS BINARY(4)) AS VARBINARY(900))
FROM Employees AS E
JOIN EmpCTE AS M
ON E.mgrid = M.empid
SELECT
REPLICATE(' | ', lvl)
+ '(' + (CAST(empid AS VARCHAR(10))) + ') '
+ empname AS empname
FROM EmpCTE
ORDER BY sortcol
(1) Nancy
| (2) Andrew
| | (5) Steven
| | (6) Michael
| (3) Janet
| | (7) Robert
| | | (11) David
| | | | (14) James
| | | (12) Ron
| | | (13) Dan
| | (8) Laura
| | (9) Ann
| (4) Margaret
| | (10) Ina
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
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Large scale of database and data cleansing
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Set operator Vs Self join

hi all,
i have a main table and a corresponding history table.
Like employee and h_employee both has primary key as emp_id.
now i want a query which should only retrieve the common values among these two table.
I have an idea of doing this in two way 1.self join 2. set operator
1.select emp_id
from emp e,h_emp h
using (emp_id)
2. select emp_id from emp
intersect
select emp_id from h_emp
now guide me which gives better performance? how to evaluate the performance in PL/SQL Developer client?
is there any keyword to trace the timing of the each query?
Please advice.
Regards,
Slu

Set operators combines the output of 2 or more queries into single output....
Internally its doing sorting the two tables
Join is just matching the records based on the where condition ....
use Explain plan to the cost of the query
SQL> Explain plan for select emp_id
from emp e,h_emp h
using (emp_id)
and use
SQL > select * from plan_table
to see the cost...
Edited by: LPS on Jul 12, 2011 12:08 AM

Self Join

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