Hi all,
I have the following query to be optimized. It just takes too long to complete the execution.
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SELECT COUNT(*)
FROM Tbl_A a
INNER JOIN Tbl_B b
ON a.AID = b.AID
INNER JOIN Tbl_C c
ON a.AID = c.AID
INNER JOIN Tbl_D d
ON d.DID = a.DID
INNER JOIN Tbl_E e
ON e.DID = d.DID
INNER JOIN Tbl_F f
ON e.EID = f.EID
WHERE a.Col_1 = 1
AND (a.Col_2 LIKE N'%abc%')
AND a.Col_3 <>
CASE
WHEN d.Col_1 ='ABC' THEN 'BR'
ELSE ''
END
AND c.Col_1 =
CASE
WHEN d.Col_1 ='ABC' THEN 'ABC_COMPANY'
ELSE 'PPRO'
END
AND f.Col_1 = 'val1'
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here is the estimated records for the tables.
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Tbl_A has over 150,000 records
Tbl_B has over 150,000 records
Tbl_C has over 450,000 records
Tbl_D has over 33 records
Tbl_E has over 4000 records
Tbl_F has over 5000 records
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How to optimize the following Stored procedure running on MSSQL server 2000 sp4 :
CREATE PROCEDURE proc1 @Franchise ObjectId , @dtmStart DATETIME , @dtmEnd DATETIME AS BEGIN
SET NOCOUNT ON
SELECT p.Product , c.Currency , c.Minor , a.ACDef , e.Event , t.Dec , count(1) "Count" , sum(Amount) "Total" FROM tb_Event t JOIN tb_Prod p ON ( t.ProdId = p.ProdId ) JOIN tb_ACDef a ON ( t.ACDefId = a.ACDefId ) JOIN tb_Curr c ON ( t.CurrId = c.CurrId ) JOIN tb_Event e ON ( t.EventId = e.EventId ) JOIN tb_Setl s ON ( s.BUId = t.BUId and s.SetlD = t.SetlD ) WHERE Fran = @Franchise AND t.CDate >= @dtmStart AND t.CDate <= @dtmEnd AND s.Status = 1 GROUP BY p.Product , c.Currency , c.Minor , a.ACDef , e.Event , t.Dec
Hi, Can anyone help me optimize the SELECT statement in the 3rd step? I am actually writing a monthly report. So for each employee (500 employees) in a row, his attendance totals for all days in a month are displayed. The problem is that in the 3rd step, there are actually 31 SELECT statements which are assigned to 31 variables. After I assign these variable, I insert them in a Table (4th step) and display it. The troublesome part is the 3rd step. As there are 500 employees, then 500x31 times the variables are assigned and inserted in the table. This is taking more than 4 minutes which I know is not required :). Can anyone help me optimize the SELECT statements I have in the 3rd step or give a better suggestion. DECLARE @EmpID, @DateFrom, @Total1 .... // Declaring different variables SELECT @DateFrom = // Set to start of any month e.g. 2007-06-01 ...... 1st Loop (condition -- Get all employees, working fine) BEGIN SELECT @EmpID = // Get EmployeeID ...... 2nd SELECT @Total1 = SUM (Abences) ...... 3rd FROM Attendance WHERE employee_id_fk = @EmpID (from 2nd step) AND Date_Absent = DATEADD ("day", 0, Convert (varchar, @DateFrom)) (from 1st step) SELECT @Total2 ........................... same as above SELECT @Total3 ........................... same as above INSERT IN @TABLE (@EmpID, @Total1, ...... @Total31) ...... 4th Iterate (condition) to next employee ...... 5th END It's only the loop which consumes the 4 minutes. If I can somehow optimize this part, I will be most satisfied. Thanks for anyone helping me....
Trying to optimize a query, and having problems interpreting the data. We have a query that queries 5 tables with 4 INNER JOINS. When I use INNER HASH JOIN, this is the result:
(Using SQL Programmer)
SQL Server Execution Times: CPU time = 40 ms, elapsed time = 80 ms.
Now, when timing the code execution on my ASP page, it's "faster" not using the HASH. Using HASH, there are a few Hash Match/Inner Joins reported in the Execution Plan. Not using HASH, there are Bookmark Lookups/Nested Loops.
My question is which is better to "see": Boomark Lookups/Nested Loops or Hash Match/Inner Joins for the CPU/Server?
IS there any way to rewrite this Query in optimized way?
SELECT dbo.Table1.EmpId E from dbo.Table1 where EmpId in( SELECT dbo.Table1.EmpId FROM (SELECT DISTINCT PersonID, MAX(dtmStatusDate) AS dtmStatusDate FROM dbo.Table1 GROUP BY PersonID) derived_table INNER JOIN dbo.Table1 ON derived_table.PersonID = dbo.Table1.PersonID AND derived_table.dtmStatusDate = dbo.Table1.dtmStatusDate))
How can I optimized the following query: (SELECT e.SID FROMStudents s JOINTable1e ON e.SID= s.SID JOINTable2 ed ON ed.Enrollment = e.Enrollment JOINTable3 t ON t.TNum = e.TNum JOINTable4 bt ON bt.TNum = t.TNum JOINTable5 b ON b.Batch = bt.Batch JOIN IPlans i ON i.IPlan = ed.IPlan JOINPGroups g ON g.PGroup= i.PGroup
WHERE t.TStatus= 'ACP' ANDed.EStatus= 'APR' ANDe.SID=(select distinct SID from Table1 where Enrollment=@DpEnrollment)) AND(ed.EffectiveDate= (SELECT EffectiveDate FROM Table2 ed JOIN Table1 e ON e.enrollment=ed.enrollment WHERE IPlan = @DpIPlan ANDTCoord = @DpTCoord ANDAGCoord= @DpAGCoord ANDDCoord=@DpDCoord ) ANDDSeq= @DpDSeq) ANDe.SID= (select distinct SID from Table1 where Enrollment=@DpEnrollment)) ) ANDed.TerminationDate= (SELECT TerminationDate FROM Table2 ed JOIN Table1 e ON e.enrollment=ed.enrollment WHERE IPlan = @DpIPlan ANDTCoord = @DpTCoord ANDAGCoord= @DpAGCoord ANDDCoord= @DpDCoord ) ANDDSeq= @DpDSeq) ANDe.SID= (select distinct SID from Table1 where Enrollment=@DpEnrollment)) ) ))
DECLARE @PTEffDate_tmp AS SMALLDATETIME SELECT @PTEffDate_tmp = DateAdd(day, -1, PDate) FROM PDates pd WHERE iplan = @DIPlan and pd.TCoord = @DTCoord and DType = 'EF'
DECLARE @PTCoord_tmp as char(3) SELECT @PTCoord_tmp = tc.TCoord FROM PDates pd JOIN TCoords tc ON (pd.TCoord = tc.TCoord) WHERE pd.Iplan = @DIPlan and tc.TGroup = @TGroup_tmp and PDate = @PTEffDate_tmp and DateType = 'TR1'
DECLARE @EStatus_tmp as char(3) SELECT @EStatus_tmp = EDStatus From EDetails ed JOIN ENR e ON (ed.enr = e.enr) JOIN Trans t ON (e.transID = t.TransID) WHERE iplan = @DIPlan and ed.TCoord = @PTCoord_tmp and t.TransS= 'ACP' and DCoord = @DCoord and CEnr is null
How can I optimazed my query. Since my DB is more then 1 mln it takes a while to do all those join? select * FROM EEMaster eem JOIN NHistory nh ON eem.SNumber = nh.SNumber OR eem.OldNumber = nh.SNumber OR eem.CID = (Replicate ('0',12-len( nh.SNumber))+ nh.SNumber )
I work on tables containing 10 million plus records. What are the general steps needed to ensure that my queries run faster? I know a few: - The join fields should be indexed -Selecting only needed fields -Using CTE or derived tables as much as I can -Using good table reference eg select a.x , b.y from TableA a inner join TableB b on a.id = b.id
I will be happy if somebody could share or add more to my list.
Dear all, The below query take 7 min to execute so i want optimize the query.please any suggestions..........
SELECT DISTINCT VC.O_Id C_Id, VC.Name C_Name,VB.Org_Id B_Id, VB.code S_Code,VB.Name S_Name, mt12.COLUMN003 M_D_Code, mt12.COLUMN004 M_D_Name,CQ.COLUMN004 R_Code, CQ.COLUMN005 R_Date, CQ.COLUMN006 Ser,CQ.COLUMN008 R_Nature, CQ.COLUMN011 E_Date,mt26.COLUMN003 W_Code, mt26.COLUMN004 W_Name, mt17.COLUMN005 V_Code,mt17.COLUMN006 V_Name, mt19.column002 I_Code, mt19.column003 I_Name, mt19.COLUMN0001 R_I_No,mt92.COLUMN001 B_Id, mt92.COLUMN005 B_No, CASE mt92.COLUMN006 WHEN '0' THEN 'Ser' WHEN '1' THEN 'Un-Ser' WHEN '2' THEN 'Ret' WHEN '3' THEN 'Retd' WHEN '4' THEN 'Rep' WHEN '5' THEN 'Repd' WHEN '6' THEN 'Con' WHEN '7' THEN 'Cond' ELSE mt92.COLUMN006 END S_C_Type, mt20.COLUMN003 T_G_Code,mt20.COLUMN004 T_G_Name, V.U_Code,V.U_Name, mt19.column005 I_Quantity,mt20.COLUMN003 T_Code, mt20.COLUMN004 T_Name, mt59.COLUMN005 T_Price,VR.code C_L_Code, VR.Name C_L_Name FROM tab90 CQ INNER JOIN tab91 mt19 ON mt19.COLUMN002 = CQ.COLUMN001 LEFT JOIN tab92 mt92 ON mt92.COLUMN002 = CQ.COLUMN001 LEFT JOIN tab93 mt93 ON mt93.COLUMN004 = CQ.COLUMN001 INNER JOIN tab12 mt12 ON mt12.COLUMN001 = CQ.COLUMN003 LEFT JOIN tab26 mt26 ON mt26.COLUMN001 = CQ.COLUMN009 LEFT JOIN tab20 mt20 ON mt20.COLUMN001 = mt93.COLUMN005 LEFT JOIN tab59 mt59 ON mt59.COLUMN002=mt20.COLUMN001 LEFT JOIN tab17 mt17 ON mt17.COLUMN001 = CQ.COLUMN010 INNER JOIN VM V ON V.UOM_ID = mt19.COLUMN004 INNER JOIN tab19 mt19 ON mt19.COLUMN001 = mt19.COLUMN003 INNER JOIN vOrg VR ON CQ.COLUMN007 = VR.Org_Id INNER JOIN vOr VB ON CQ.COLUMN002 = VB.Org_Id INNER JOIN vOr VC ON VB.Top_Parent = VC.Org_Id WHERE CQ.COLUMN005 Between '02/01/2007' and '08/25/2008' And VC.O_Id in ('fb243e92-ee74-4278-a2fe-8395214ed54b')
LATEST column value changes for Row 1 since there is a repetition of value 124, meaning this row is no longer the latest.
NEW COLUMN value changes for ROW 2 since there it is no longer new; we already have an occurrence of 124 in the first row.
I m not sure if i can solve this query using any option other than cursor. it will be like taking first row --> comparing it with all the other rows and then moving further.
Plz. suggest me if there is a better approach for doing this
(SELECT add_house FROM hs_address WHERE add_id = do_address_registration_id) as add_house, (SELECT add_flat FROM hs_address WHERE add_id = do_address_registration_id) as add_house,
..... FROM hs_donor WHERE do_id = 400
Fields add_flat and add_house belong to one table. How one may optimize this query?
I am writing a query which will display employee details who is handling maximum number of projects. Here I am joining 2 tables. one is LUP_EmpProject, which contain employee id and project id and project date, in this table I have used a composite primary key of employee id, project id and project date. The other table is
EmployeeDetails which contain employee names and employee id.
I want to display the details of the employee who is handling maximum projects. Below given is the code which is working fine. But the query is taking time to execute it. Any body know how to optimize the code so that I can get the result quickly.
Code Snippet SELECT EmployeeDetails.FirstName+' '+EmployeeDetails.LastName AS EmpName, COUNT(LUP_EmpProject.Empid) AS Number_Of_Projects FROM LUP_EmpProject INNER JOIN EmployeeDetails ON LUP_EmpProject.Empid=EmployeeDetails.Empid GROUP BY EmployeeDetails.FirstName+' '+EmployeeDetails.LastName, LUP_EmpProject.Empid HAVING COUNT(LUP_EmpProject.Empid)>0 AND COUNT(LUP_EmpProject.Empid)=(SELECT MAX(Number_Of_Projects) FROM (SELECT COUNT(LUP_EmpProject.Empid) Number_Of_Projects FROM LUP_EmpProject GROUP BY LUP_EmpProject.Empid)AS sub)
max(f1.WeekValue)/case when max(f2.WeekValue) = 0 then NULL else max(f2.WeekValue) end,
@GroupOrder,@MetricOrder --from @temptable
from @FinalData f1 inner join @FinalData f2 on f1.weekdate = f2.weekdate
where (f1.Grouptitle = @GroupPFR and f1.MetricName = '$ Products')
and ( f2.Grouptitle = @GroupRevenue and f2.MetricName = 'Net Revenue')
group by f1.weekdate
There are many calculations like this in my procedure. and It takes like 3 min to run whole procedure now as I am doing group by.. So In Execution plan it show me that 60% of the query time is take n by SORT operation.. can any one give me any other option to do this.
I have a small tricky problem here...need help of all you experts.
Let me explain in detail. I have three tables
1. Emp Table: Columns-> EMPID and DeptID 2. Dept Table: Columns-> DeptName and DeptID 3. Team table : Columns -> Date, EmpID1, EmpID2, DeptNo.
There is a stored procedure which runs every day, and for "EVERY" deptID that exists in the dept table, selects two employee from emp table and puts them in the team table. Now assuming that there are several thousands of departments in the dept table, the amount of data entered in Team table is tremendous every day.
If I continue to run the stored proc for 1 month, the team table will have lots of rows in it and I have to retain all the records.
The real problem is when I want to retrive data for a employee(empid1 or empid2) from Team table and view the related details like date, deptno and empid1 or empid2 from emp table. HOw do we optimise the data retrieval and storage for the table Team. I cannot use partitions as I have SQL server 2005 standard edition.
Please help me to optimize the query and data retrieval time from Team table.
I need help in optimizing this query. The major time takes in calling a remote database. Thanks in advance.ALTER PROCEDURE dbo.myAccountGetCallLogsTest@directorynumber as varchar(10),@CallType as tinyint ASdeclare @dt as intSELECT TOP 1 @dt=datediff(day,C.EstablishDate,getdate())FROM ALBHM01CGSERVER.Core.dbo.Customer C INNER JOIN ALBHM01CGSERVER.Core.dbo.UsgSvc U ON C.CustID = U.CustIDWHERE (U.ServiceNumber = @directoryNumber)ORDER BY C.EstablishDate DESCIF @dt>90select DN as Number, Remote_DN as [Remote Number], City, StartTime as [Start Time], EndTime as [End Time] from vw_Call_Logs where DN = '1' + @directoryNumber and call_type = @CallType and datediff(day,starttime,getdate())<90order by starttime descELSE select DN as Number, Remote_DN as [Remote Number], City, StartTime as [Start Time], EndTime as [End Time] from vw_Call_Logs where DN = '1' + @directoryNumber and call_type = @CallType and datediff(day,starttime,getdate())< @dtorder by starttime desc
select count(a.callid) from tbl1 as a inner join tbl2 as b on a.calldefid=b.calldefid where a.programid=175
select count(a.callid) from tbl1 as a inner join tbl2 as b on a.calldefid=b.calldefid where b.programid=175
callid - pk on tbl1 calldefid - nonclustered index on both tbl1 and tbl2 programid - nonclustered index on both tbl1 and tbl2 tbl2 is the smaller table
from my understanding, the second query will run faster because you reduce the records in the smaller table, then join to the larger table (tbl1).
but can you explain to me why limiting the rows on tbl1 first, then joining to tbl2 would take longer?
Hello Eveybody,I have just joined as DBA.My problem will be simple for you allgurus.I have a table with 50 lakh row,when i am writing a selectstatement for this table it takes around 7 minute to display result.Iused DBCC REINDEX for this table but it was not effective.So please pass ur suggestion that i should follw to reduce myexecution time.As its effecting my server performance.Thank u in advancevv
How does the phrase "Is Not Null" in the where clause effect theeffectiveness of a query?If it is a determent to the effectiveness of the query, how do youwork around it?Thanks,
I'm trying to optimize some queries on an existing system, and I'mnoticing some odd behavior. I'm performing a join between severaltables, the final table being joined by the optimizer has a clusteredindex on the field that it is using to join to the rest of the query,but for some reason SQL Server doesn't seem to actually use this index(it's doing an index scan instead of an index seek). Is there somereason why SQL Server would not use a valid Clustered Index? I'vedropped and readded the index, but that doesn't seem to help. I don'tknow if it would be relevant, but the tables I'm working on are fairlyfat (2 to 7K bytes/row).This is happening for several tables. I've been able to get around itfor some of the tables by creating a non-clustered index on all thefields that are being queried so that the leaf pages don't need to beloaded, but this isn't a valid solution for all of the tables I'mstruggling with.Any ideas? (and no, they aren't willing to redesign any of thetables).
Hi,Need help in optimizing a query in SQL Server.Following is the problem statement.There are two tables;1st table (t1) has a KEY ( char(8) ) column, with a clustered index.this is not the primary key. The table can have billions of records;in test environment, we are having 3,000,000 records2nd table (t2) has two columns a from_Range and to_Range, bothchar(8). this table has lesser number of records, in thousands.Clustered index is on the primary key.However there is no relation whatsoever between the KEY and thefrom/to range.We need to find matching records where Key is found between the fromand to range :select t1.id, t2.id from t1, t2where t1.KEY between t2.from_range and t2.to_range( The ids form part of primary keys in both tables. )The plan shows a loop, with t1 using clustered index of KEY and t2using clustered index of the primary key.This query is taking around 14 seconds on SQL server 2000 in win2kprowith P4 and 512 MB RAM.Is there any way this can be reducd to a subsecond performance ? Thisquery forms the core of most of the processing, and any reduction herewill have recursive effect all over.Thanks in advance,roy.
I need to write query wherein i want to order records by a multi valued atrribute and select distinct ids but in the same order. It can be explained better by follwing example:
Selecting distinct Departments in the alphabetical order of their Heads: Quer 1:
select dept, headfrom deptHead
order by head
This query gives me Departments in sorted order but duplicate records come because Head is a multi-valued attribute.
Query 2:
select distinct dept from
(select top 100 percent dept from deptHead
order by head
)temp
This query gives me distinct Departments but the Order is lost. The order of inner query is lost in the outer query result.
Query 3:
select top 100 percent ROWNUM = IDENTITY(int,1,1) , dept into #temp from deptHead
order by head
select distinct dept, min(ROWNUM) from #temp
group by dept
order by min(ROWNUM)
drop table #temp
This query does the job but it involves the use of a Temporary Table since ROWNUM can't be without a "select into" clause. And since this is a simplified version of my actual query wherein tables have large number of rows its affecting the performance very badly.
I'm have made a series of tables and views to create some reports. I have included boiled-down versions of them below. The report query that I want to run (at the bottom) takes a long time to execute and sometimes times out. Creating a rank within the query is doing the most damage, but it can still take a long time to execute without it. The usage table has almost 70k records and there are over 10k users. Does anyone have suggestions for making these views/queries more efficient?
CREATE VIEW VUsageSubtotals AS SELECT TOP 100 PERCENT VUserGroupDates.strUserID, people.name, VUserGroupDates.intGroupID, usage.accesstype, SUM(usage.cost) AS subtotal, MONTH(usage.gmttime) AS [month], VUsageTotals.total FROM VUserGroupDates INNER JOIN people ON VUserGroupDates.strUserID = people.strUserID INNER JOIN usage ON people.strUserID = usage.strUserID INNER JOIN VUsageTotals ON VUserGroupDates.strUserID = VUsageTotals.strUserID AND VUserGroupDates.intGroupID = VUsageTotals.intGroupID AND MONTH(usage.gmttime) = VUsageTotals.[month] WHERE (usage.gmttime BETWEEN VUserGroupDates.dtJoinDate AND VUserGroupDates.dtLeaveDate) GROUP BY VUserGroupDates.strUserID, VUserGroupDates.intGroupID, usage.accesstype, MONTH(usage.gmttime), VUsageTotals.total
==========================
CREATE VIEW VUsageTotals AS SELECT VUserGroupDates.strUserID, people.name, VUserGroupDates.intGroupID, SUM(usage.seconds) AS totaltime, SUM(usage.cost) AS totalcost, MONTH(usage.gmttime) AS [month] FROM VUserGroupDates INNER JOIN people ON VUserGroupDates.strUserID = people.strUserID INNER JOIN usage ON people.strUserID = usage.userid WHERE (usage.gmttime BETWEEN VUserGroupDates.dtJoinDate AND VUserGroupDates.dtLeaveDate) GROUP BY VUserGroupDates.strUserID, people.name, VUserGroupDates.intGroupID, MONTH(usage.gmttime)
==========================
CREATE VIEW VUserGroupDates AS SELECT strUserID, intNewGroupID AS intGroupID, dtJoinDate, ISNULL ((SELECT MAX(TGA2.dtJoinDate) FROM TGroupAudit TGA2 WHERE TGA2.dtJoinDate < TGA1.dtJoinDate AND TGA2.strUserID = TGA1.strUserID), GETDATE()) AS dtLeaveDate FROM TGroupAudit TGA1
==========================
Here's a sample query that gets run for a report:
SELECT TOP 30 PERCENT WITH TIES V1.*, (SELECT COUNT(DISTINCT V2.subtotal) FROM VUsageSubtotals V2 WHERE V1.subtotal <= V2.subtotal AND V1.intGroupID = V2.intGroupID AND V2.month = 3) AS rank FROM VUsageSubtotals V1 WHERE strUserID IN ('a1, a2, b5, b7, b9, d12') AND V1.month = 3 AND accesstype = 'STANDARD' GROUP BY strUserID, intGroupID, subtotal, month, total, accesstype
The purpose of the report is an accounting one. It is desired to know how much each user used each accesstype during a month. Usage is further split up by the user's groups (which may never change or could several times during a month) for billing purposes.
Hi, I need an advice from some SQL Guru. I have a Cursor (SQL Server 2005) which calculates the monthly employee wages. The outer query selects all the employees and the inner query computes the monthly salary day by day in a loop. For each day in a month, i insert a record in a temporary table. So for 2 employees, there can be 2 x 31 records (31 are the maximum days in a month). Later i rotate the temporary table to convert the 31 rows for each employee into one record so at the end there are only 2 employee records but with 31 columns. The problem is that the rotation is taking a huge performance hit and almost takes 5 minutes to convert rows to columns. I have even tried the PIVOT statement but that too almost takes the same time. Could anyone suggest me how can i nail down a performance efficient query for a monthly report. As far as i know, even on Mainframes, monthly/annual reports takes a long time to compile. So if any GURU has a better idea, i would really appreciate it. I am only asking about how would any Guru/Expert handle monthly/annual reports with huge amount of data in the tables efficiently. Regards.........
It is said that, aimed at the same task, different SQL Select Statements maybe have different efficiency. Microsoft Corp. has provided the tool,Query Analyzer, but I have not any idea.
I have the following table structure: tableA (~85,000 rows) primary key = [colA,colB] tableB (~850,000 rows) primary key = [colA,colC] tableC (~120,000,000 rows) primary key = [colA,colB,colC]
IMPORTANT: colC is DATETIME
For a SET of rows in tableA (about 50,000) I need to pull the MOST RECENT (given a date) corresponding values from tables B and C. The only way I can think of doing this is the following:
SELECT tableA.colA ,(SELECT TOP 1 colX FROM tableB WHERE colA = tableA.colA AND colC <= @INPUTDATE ORDER BY colC desc) ,(SELECT TOP 1 colY FROM tableB WHERE colA = tableA.colA AND colC <= @INPUTDATE ORDER BY colC desc) ,... --some more columns from tableB ,(SELECT TOP 1 colX FROM tableC WHERE colA = tableA.colA AND colB = tableA.colB AND colC <= @INPUTDATE ORDER BY colC desc) ,(SELECT TOP 1 colY FROM tableC WHERE colA = tableA.colA AND colB = tableA.colB AND colC <= @INPUTDATE ORDER BY colC desc) ,... --some more columns from tableC FROM tableA WHERE tableA.colX = 'some criteria'
Is there any other way anyone can suggest? Unfortunately, because tableC is so large, the disk IO (I think) causes this query to take over an hour. (If I had monster RAM and super fast disk this wouldn't be as big an issue, but that's not an option right now )
Query #1:select <list of fields>from Cjoin B on C.b_key = B.b_keyjoin A on B.a_key = A.a_keywhere A.o_key = <some value>Query #2:select <list of fields>from Cwhere b_key in (select b_keyfrom Bwhere a_key in (select a_keyfrom Awhere o_key = <some value>))#1 (and other things with the same general pattern) are used inliterally thousands of places in this one client's system, and ismuch nicer to write, but seems to be rather slower than #2. Isthere any way to tweak the tables to tell the system somethinglike "hey, B, whenever you're joined to A, you should seriouslyconsider waiting for A to be filtered down to a manageable levelfirst"? And similarly for C/B.MS SQL 2000, SP3, 6.5 compat mode. These are set in stone untilwe upgrade the accounting software (highly non-trivial).
