SQL Query rewrite, remove ORDER BY clause

Hello,
we've just installed a proprietary application which uses an Oracle 11.2.0.2 RAC database. We've seen that one of the auto-generated application's queries
has poor performance (3-5 minutes for results), the query does a SELECT and at the end it uses an ORDER BY clause. If we remove the ORDER BY clause
the query returns the results in less than 5 seconds. Unfortunately, we can't re-write the query in the application since we don't have any access to it and
i was wondering if there is a way to rewrite the specific query from the database.
We've already seen the SQL Patch but we can change only the hints of the query so we can't remove the ORDER BY clause from it. From what we've seen
outlines also change only the hints and not the actual sql statement.
Is there a way to rewrite the specific query from the database ?
thanks in advance,
Giannis

Maybe DBMS_ADVANCED_REWRITE can help but this a SQL question than has very likely nothing to do with RAC.
See http://www.oracle-base.com/articles/10g/dbms_advanced_rewrite.php.

Similar Messages

Problem in sql query because of order by clause

Hi All,
I am facing a one problem in my one sql query.I am using Oracle 10gR2.
Query is given below:
SELECT t1.ename
        FROM T1, T2
       WHERE T1.EMPNO = 1234
         AND T1.ACCOUNTNO = T2.ACCOUNTNO
         AND T1.SEQ = T2.SEQ
       ORDER BY T2.SEQThe Plan of the query is :
| Id | Operation                     | Name                 | Rows | Bytes | Cost (%CPU)| Time     |
|   0 | SELECT STATEMENT              |                      |     2 |   218 | 11716   (1)| 00:00:41 |
|* 1 | TABLE ACCESS BY INDEX ROWID | T1                   |     1 |    89 |     1   (0)| 00:00:01 |
|   2 |   NESTED LOOPS                |                      |     2 |   218 | 11716   (1)| 00:00:41 |
|* 3 |    TABLE ACCESS BY INDEX ROWID| T2                   |     2 |    40 | 11715   (1)| 00:00:41 |
|   4 |     INDEX FULL SCAN           | PK_T2_SEQ            | 58752 |       |   122   (5)| 00:00:01 |
|* 5 |    INDEX RANGE SCAN           | FK_ACCOUNTNO         |     3 |       |     0   (0)| 00:00:01 |
----------------------------------------------------------------------------------------------------Now i want to reduce the time of this query.
If i am removing Order by clause from query than performance of the query is totally perfect but with order by clause its taking a time.
I have already set SORT_AREA_SIZE but still nothing is improving.
Welcome and thanks for your suggestions.
Thanks,
Edited by: BluShadow on 23-Jun-2011 07:55
added {noformat}{noformat} tags and formatted explain plan to make it readable. Please see {message:id=9360002} for details on how to post code and data

Hi,
There are a couple of things I do not understand.
1. Why don't you put {noformat}{noformat} around your code, it makes it so much easier to read, especially your explain plan
2. You claim that the ORDER BY is problematic compared to no order by. Then why do you choose to post only one plan?
3. It is hard to understand how your tables relate, and which indexes you have and which you don't.
- PK_T2_SEQ, does this mean that SEQ alone is primary key of T2?
- If SEQ is primary key of T2, why do you join on accountno, seq and not just seq?
- If SEQ is primary key of T2 one of the tables is denormalized.
4. FK_ACCOUNTNO, is this an index on accountno, alone?
- Or is this AccountNo, Seq?
5. Is there no index on T1.EMPNO?
Above could of course just be a case of my not understanding the names of your indexes.
So, here are my guesses:
Above plan is for the ORDER BY query. That means the optimizer, has chosen to full scan PK_T2_SEQ, since data is then read according to the ORDER BY.
(This could be a bad choice)I
You could try and order by t1.seq, instead. Result should be the same.
Regards
Peter

Problem with SQL query region source containing OLAP clauses

Hi team,
I believe I found a bug when HTMLDB validates the SQL Query in a report region.
My query includes an ORDER BY clause within a windowing function and HTMLDB refuses to accept the source owing to the presence of the ORDER BY and the column heading sort preference.
Clearly the order-by in a window function has little to do with the column heading sort, but this error prevents me from updating the conditional display item in the page definition.
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So, in the end, if I don't change anything the page works because the sql query is assumed to be correct but unfortunately I need to change the condition and I cannot.
The problem shows up in page 126 of app 21670, SQL query region.
Bye,
Flavio
PS: may be I can work around this by using the pl/sql function returning the sql query.

Flavio,
We're aware of this problem. For now, your workaround is described in this thread:
HTMLDB 1.6 and "order by" in analytic functions
Sergio

How to write a SQL Query without using group by clause

Hi,
Can anyone help me to find out if there is a approach to build a SQL Query without using group by clause.
Please site an example if is it so,
Regards

I hope this example could illuminate danepc on is problem.
CREATE or replace TYPE MY_ARRAY AS TABLE OF INTEGER
CREATE OR REPLACE FUNCTION GET_ARR return my_array
as
     arr my_array;
begin
     arr := my_array();
     for i in 1..10 loop
          arr.extend;
          arr(i) := i mod 7;
     end loop;
     return arr;
end;
select column_value
from table(get_arr)
order by column_value;
select column_value,count(*) occurences
from table(get_arr)
group by column_value
order by column_value;And the output should be something like this:
SQL> CREATE or replace TYPE MY_ARRAY AS TABLE OF INTEGER
2 /
Tipo creato.
SQL>
SQL> CREATE OR REPLACE FUNCTION GET_ARR return my_array
2 as
3   arr my_array;
4 begin
5   arr := my_array();
6   for i in 1..10 loop
7    arr.extend;
8    arr(i) := i mod 7;
9   end loop;
10   return arr;
11 end;
12 /
Funzione creata.
SQL>
SQL>
SQL> select column_value
2 from table(get_arr)
3 order by column_value;
COLUMN_VALUE
           0
           1
           1
           2
           2
           3
           3
           4
           5
           6
Selezionate 10 righe.
SQL>
SQL> select column_value,count(*) occurences
2 from table(get_arr)
3 group by column_value
4 order by column_value;
COLUMN_VALUE OCCURENCES
           0          1
           1          2
           2          2
           3          2
           4          1
           5          1
           6          1
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SQL> Bye Alessandro

Help: PL/SQL passing paramter to ORDER BY clause

I am working on a procedure that using a parameter to pass sorting order. If there parameter, say p_order which is varchar2, can I just use the it directly passing the field name to the order by clause?
What I really want to know is that do I have to use decode together with p_order to achieve the goal?
WJH

Hi,
The positional notaion in ORDER BY, e.g.
ORDER BY 2, 1is one of the rare cases in which a numeric literal is required. Using an expression, even a bind variable, won't raise an error, but won't sort, either. (It's equivalent to sorting by a constant, which doesn't sort at all.)
Like Centinul said, you have to use dynamic SQL to construct the ORDER BY clause, or use some kind of IF-THEN-ELSE logic (such as CASE), like this:
SELECT    ename, sal
FROM      scott.emp
ORDER BY CASE
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SQl query to remove all dbms_output statement

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Umesh

>
Can u please tell me Single SQl query to remove all
dbms_output statement from package and procedure
If you are comfortable with scripting languages like Perl, Python, Ruby etc., then removing lines having the dbms_output statements from your files should be a trivial matter.
pratz

How to order SQL query results in order given in IN Clause

Hi,
I Need to construct a query, which takes a string as input and results for those should be sorted in the order in which request was made.
Say, we have a couple of students, and the grades in different subjects to be the result of the query.
If John and Jane are the two students,
and if input is John,Jane
my output should be listing John, his subjects and grades
and then Jane, her subjects and grades.
I read somewhere in other posts, that i could use a query combined with regular expression to split a string into a temp table/array and use this as my input for my select query. Then use the rownum or level from this temp table to sort the data in order sent in.
But am not able to put together a query which would work for me.
Anyone with any pointers on this would be highly appreciated.
Thanks

Hi,
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Need sql query to remove duplicates using UNION ALL clause

Hi,
I have a sql query which has UNION clause.But the UNION clause is causing some performance issues.
To overcome that I have used UNION ALL to improve performance but its returning duplicates.
Kindly anyone send a sample SQL query where my primary objective is used to use UNION ALL clause and to consider unique rows (elimating duplicate
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why not UNION? :(
another way also use MINUS
SQL>
SQL> with t as
2 (
3 select 1 if from dual union all
4 select 2 if from dual union all
5 select 1 if from dual union all
6 select 3 if from dual union all
7 select 3 if from dual
8 )
9 ,t2 as
10 (
11 select 1 if from dual union all
12 select 2 if from dual union all
13 select 3 if from dual union all
14 select 4 if from dual union all
15 select 5 if from dual
16 )
17 (select if from t
18 union all
19 select if from t2)
20 /
        IF
         1
         2
         1
         3
         3
         1
         2
         3
         4
         5
10 rows selected
SQL> so
SQL>
SQL> with t as
2 (
3 select 1 if from dual union all
4 select 2 if from dual union all
5 select 1 if from dual union all
6 select 3 if from dual union all
7 select 3 if from dual
8 )
9 ,t2 as
10 (
11 select 1 if from dual union all
12 select 2 if from dual union all
13 select 3 if from dual union all
14 select 4 if from dual union all
15 select 5 if from dual
16 )
17 (select if from t
18 union all
19 select if from t2)
20 minus
21 select -99 from dual
22 /
        IF
         1
         2
         3
         4
         5
SQL>

Sql count function in order by clause

Post Author: krypton
CA Forum: Data Connectivity and SQL
Hi Guys
Can i ask a quick question. I am trying to retrieve data remotely from a SQL Server via crystal reports.
Within the Database Expert I have entered a SQL query to retrive the number of (call center) support calls raised by our customers:-
Select `Primary_Company`, COUNT(`Calls`)From `SPRT_Issue` GROUP BY `Primary_Company`ORDER BY COUNT(`Calls`) desc
The customer's column is called 'Primary Company' and the calls they raise are in the 'Calls' column. the above is a normal sql query.
However Crystal fails to run the query and generates an error message :-
Failed to open a rowset. Details: 420: Driver] Expected lexical element not found: <identifier>
I dont understand why it wont run. In the ORDER BY clause if i replace field 'Calls' by the field 'Primary Company' then it works.
I think the problem is that it wont accept the count function in the order by clause. which is what i want it to do i.e display the calls in descending order by each customer.
Could someone tell me if there is a way around it.
Thanks
Krypton

Post Author: krypton
CA Forum: Data Connectivity and SQL
Thanks Lynn
I tried your suggestion. But there is one probelm.
When i sort the data in descending order using the count(calls) field, the data is returned but the customer's name appears multiple times along with their calls raised.
E.g, if customer Mark raised multiple calls i.e. 2, 5, and 10 calls, then the report will show
Mark 2
Mark 5
Mark 10
But is there a way to aggregate all the calls for mark and show them only once:
such as Mark 17
Thanks

Visual Web - How to 'setObject' for an SQL query with an IN ? clause

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setObject(1, whatevervalue);
How do we pass parameters if we need to check for more than one variable? The query editor in VWP has the option IN, which allows us to check for more than one match in a column. The IN clause is supposed to allow the format ('ex1', 'ex2' ...). I tried using an array as a parameter, like, setObject(1, somearray). It gives me a null exception. I even tried sending a variable in ('ex1', 'ex2' ...) format; doesn't like it either.
Any help is greatly appreciated.

Check the following docs:
http://www.netbeans.org/kb/60/web/databoundcomponents.html
http://www.netbeans.org/kb/60/web/inserts-updates-deletes.html
See also:
http://developers.sun.com/jscreator/reference/techart/2/query-editor.html

Using Parameters in SQL-Query not only in where clauses

Hi,
I try to use Publisher parameters in the SQL Query from a Data Set.
All of them have default values.
So far, this is no problem, unless I try to use such a parameter value as an ordinary attribute value:
>
select
 case when (:pv_Group = 'no') then "DM15D_BETRIEBSTEIL"."BETR_TEIL"
 else :pv_some_Text end as Betr_Teil,
 case when (:pv_Group = 'no') then "DM15D_BETRIEBSTEIL"."SUVA_NR_FORM"
 else :pv_some_Text end as Suva_Nr,
 case when (:pv_Group = 'no') then "DM15K_RIS_FAKTEN_PRO_BTT_JHR"."RIS_VOLLBESCH"
 else sum("DM15K_RIS_FAKTEN_PRO_BTT_JHR"."RIS_VOLLBESCH") end as Vollbesch
from "GDWH05"
where
 "DM15D_BETRIEBSTEIL"."SUVA_NR_FORM" in (:pv_nim100)
 fetch first 65001 rows ONLY
>
The parameters 'pv_Group' and 'pv_nim100' are working fine. (when or where clauses)
The parameter 'pv_some_Text' unfortunately not. (simple literals)
When I try to validate the above SQL, I get the following Error:

java.io.IOException: prepare query failed[nQSError: 43113] Message returned from OBIS. [nQSError: 46033] Datatype: 25 is not supported.

After use a cast function:
>
else CAST(:pv_some_Text AS CHARACTER)
>
I get this ERROR:

java.io.IOException: prepare query failed[nQSError: 43113] Message returned from OBIS. [nQSError: 19002] Incorrect use of parameters. The parameters used in CAST cannot be resolved without ambiguity.

We use OBIEE 11.1.1.6.4 on a Win64-System.
Thank's for any help.

Hi Alex,
let's leave away any unnecessary details.
This is the SQL, inserted in the window 'Edit Data Set' of BIP Data Model:
>
select
 '--1' as Betr_Teil,
 '--2' as Suva_Nr,
 sum("GDWH05"."DM15K_RIS_FAKTEN_PRO_BTT_JHR"."RIS_VOLLBESCH") as Vollbesch
from "GDWH05"
where
 "DM15D_BETRIEBSTEIL"."SUVA_NR_FORM" in ('122-4.4')
 fetch first 65001 rows ONLY
>
Everything is fine when I click OK, the script goes back to the metadata.
Let's try this script with bind values in ORACLE SQL Developer.
This SQL is the physical part, found in the OBIEE-Log (Log level 5), except the bind values. Therefore we find, in the where clause, the join. In the logical sql, we don't have to join, because it's handled in the Common Enterprise Information Model (CEIM)
>
with
sawith0 as
select
sum(t39617.ris_vollbesch) as c1
from
dm15d_betriebsteil t39455,
dm15k_ris_fakten_pro_btt_jhr t39617
where
t39455.id_betriebsteil = t39617.id_betriebsteil
and t39455.suva_nr_form = '122-4.4'
select
d1.c1 as c1,
d1.c2 as c2,
d1.c3 as c3
from
select
:pv_some_text as c1,
:pv_some_text as c2,
sum(d1.c1) as c3
from
sawith0 d1
d1
where
rownum <= 65001
>
This SQL works fine, even with bind values for 'pv_some_text'.
But, when using the following SQL in the BIP Data Model:
>
select
 :pv_Text as Betr_Teil,
 :pv_Text as Suva_Nr,
 sum("GDWH05"."DM15K_RIS_FAKTEN_PRO_BTT_JHR"."RIS_VOLLBESCH") as Vollbesch
from "GDWH05"
where
 "DM15D_BETRIEBSTEIL"."SUVA_NR_FORM" in ('122-4.4')
 fetch first 65001 rows ONLY
>
The following ERROR occurs:
java.io.IOException: prepare query failed[nQSError: 43113] Message returned from OBIS. [nQSError: 46008] Internal error: File server\Query\Optimizer\ServiceInterfaceMgr\Utility\Src\SQOIUTypeVisitor.cpp, line 643.
In my opinion, either I use a wrong syntax, or BIP has a problem with parsing the script.
Thank you for your most welcome help.

SEQUENCE Select within an SQL Query with an ORDER BY statement

Does anyone know why you cannot use an ORDER BY statement within an SQL query when also selecting from a SEQUENCE? My query was selecting production data as a result of a filtered search. I want to take the results of the filtered search and create a transaction. I have a sequence for generating transaction numbers where I select NEXTVAL. Since I could possibly obtain multiple, yet distinct, rows based upon my search criteria, I wanted to use an ORDER BY statement to simplify and order the resulting row(s).
I was able to get the SQL select with SEQUENCE.NEXTVAL to work without the ORDER BY, so I know that my SQL is correct. Thanks in-advance.

Okay,
I understand. You want the sequence assigned first and the you want to ORDER BY. You
can do this using pipelined functions. See here:
CREATE OR REPLACE TYPE emp_rec_seq AS OBJECT (
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   ename   VARCHAR2 (20),
   job     VARCHAR2 (20),
   sal     NUMBER
CREATE OR REPLACE TYPE emp_tab_seq AS TABLE OF emp_rec_seq;
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   RETURN emp_tab_seq PIPELINED
IS
   my_record   emp_rec_seq := emp_rec_seq (NULL, NULL, NULL, NULL);
BEGIN
   FOR c IN (SELECT dummy.NEXTVAL seq, ename, job, sal
               FROM emp)
   LOOP
      my_record.seq := c.seq;
      my_record.ename := c.ename;
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      PIPE ROW (my_record);
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END get_emp_with_sequence;after that, you can do a select like this:
SELECT seq, ename, job, sal
FROM TABLE (get_emp_with_sequence)
order by enamewhich will get you this:
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      1054 CLARK                MANAGER                    2450
      1057 FORD                 ANALYST                    3000
      1062 JAMES                CLERK                       950
      1055 JONES                MANAGER                    2975
      1052 KING                 MANAGER                   20000
      1060 MARTIN               SALESMAN                   1250
      1063 MILLER               CLERK                      1300
      1064 DKUBICEK             MANAGER                   12000
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      1058 SMITH                CLERK                       800
      1061 TURNER               SALESMAN                   1500
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http://deneskubicek.blogspot.com/
http://htmldb.oracle.com/pls/otn/f?p=31517:1
-------------------------------------------------------------------

SQL - Query rewrite ?

Hi
I have this query
SELECT a.col1,
a.col2,
a.col3,
a.col4
FROM table1 a
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FROM table1
WHERE table1.datecol <= p_date AND table1.col5 = p_number);
This is a cursor in a function so p_date and p_number are in parameters.
In the example above table1 contains abot 300 million rows, and the query does 2 scans
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Is there anyway to rewrite this SQL statment with one access only ?

Both query will not give the same results
WITH table1 AS
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union
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union
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union
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SELECT a.col1,
a.col2,
a.col3,
a.col4
FROM table1 a
WHERE a.id = (SELECT MAX (id)
FROM table1
WHERE table1.datecol <= to_date('03/01/2011','dd/mm/yyyy')
AND table1.col5 = 3);
WITH table1 AS
(select 1 id, 1 col1, 1 col2, 1 col3, 1 col4, 1 col5, to_date('01/01/2011','dd/mm/yyyy') datecol from dual
union
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union
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(SELECT
a.id,
max(a.id) over (partition by a.id order by a.id) maxid,
a.col1,
a.col2,
a.col3,
a.col4,
a.datecol,
a.col5
FROM table1 a)
WHERE datecol <= to_date('03/01/2011','dd/mm/yyyy')
AND col5 =3
AND id = maxid;Best regards
Mohamed Houri

SQL QUERY TO REMOVE ONE OF THE THE RESULT SET

Hello Everyone,
I need some advise on how to achieve the subject. My query is as follows:
select t2.post_date a, trunc(sysdate - (&num + 1))
from trans_hist t2
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and 'xxxxxxxxxxxxxxx' in
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5-JUN-2007
6-JUN-2007
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Thank you for your help.
Randy

maybe something like:
SQL> with trans_hist as
2 (select to_date('4-JUN-2007','DD-MON-YYYY') post_date from dual union all
3   select to_date('5-JUN-2007','DD-MON-YYYY') post_date from dual union all
4   select to_date('6-JUN-2007','DD-MON-YYYY') post_date from dual)
5 select * from trans_hist;
POST_DATE
04-JUN-07
05-JUN-07
06-JUN-07
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3   select to_date('5-JUN-2007','DD-MON-YYYY') post_date from dual union all
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8            from trans_hist) transaction_history
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POST_DATE
05-JUN-07
04-JUN-07
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select t3.a, t3.b
from (select t2.post_date a, trunc(sysdate - (&num + 1)) b,
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SQL Query to re-order the columns

Hello All,
I want to know if it is possible to re-order the columns of a table once the rows has been inserted in all the columns.
So for e.g I have initially a table containing 3 columns COL1, COL2 & COL3.
Now after data has been inserted into the table, I want to re-order the columns like COL3, COL2, COl1 or may be COL2, COL1, COL3 etc keeping the data intact.
Cheers,
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Parag Kalra wrote:
I want to know if it is possible to re-order the columns of a table once the rows has been inserted in all the columns.
So for e.g I have initially a table containing 3 columns COL1, COL2 & COL3.
Now after data has been inserted into the table, I want to re-order the columns like COL3, COL2, COl1 or may be COL2, COL1, COL3 etc keeping the data intact.Why? What is your reason for wanting to do this? What do you want to achieve by it? If we understand the actual problem, then we may be able to provide some usable suggestions.
The reason why your request makes very little sense is that the physical sequence of columns in a row in a datablock, has no impact on you as developer writing code.
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SQL allows you the programmer to specify the sequence of columns, and subset of columns, that you want to use in your SQL.
Why would you want to change the physical table definition, and rewrite the entire table on disk (using very expensive I/O) to reorder the physical column sequence?

SQL Query rewrite, remove ORDER BY clause

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