SQL Server compare results of two queries that should be identical

Question

I am modifying a sql server 2005 stored procedure slightly for performance, and I would like to quickly make sure the old stored proc and the new one return the exact same results (the columns are the same, I want to make sure the rows are the same).

Is there a simple way to do this in sql server 2005?

score 76 · Accepted Answer · answered Jun 13 '12 at 15:00

76

you can use the except construct to match between the two queries.

select * from (select * from query1) as query1
except
select * from (select * from query2) as query2

EDIT:

Then reverse the query to find differences with query2 as the driver:

select * from (select * from query2) as query2
except
select * from (select * from query1) as query1

answered Jun 13 '12 at 15:00

jabs

1,694
4
19
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13

Note that this will discard duplicates. Thus if query one returns 1 record and query two returns 2 records that are identical to one another and to the single record from query one, the "except" logic will return zero rows. – Paul Chernoch Sep 06 '12 at 15:38

tpvasconcelos · Answer 2 · 2022-05-18T17:12:52.020

To complete @jabs answer, you can use the following template to get the difference between two queries. It also adds an extra column (diff_description) that explains from which query each row is missing.

with q1 as (
    <INSERT_Q1_HERE>
)
, q2 as (
    <INSERT_Q2_HERE>
)
, missing_from_q2 as (
    select *
    from (
        select * from q1 
        except 
        select * from q2
    )
    cross join (select 'missing from q2' as diff_description)
)
, missing_from_q1 as (
    select *
    from (
        select * from q2 
        except
        select * from q1
    )
    cross join (select 'missing from q1' as diff_description)
)
select * from missing_from_q2
union all
select * from missing_from_q1

CodeCowboyOrg · Answer 3 · 2017-11-17T14:30:29.177

The stored proc below will compare the output resultset of 2 stored procedures, or 2 statements. The key here is the SP does not need to know the structure or schema of the result set, thus you can arbitrarily test any SP. It will return 0 rows if the output is the same. This solution uses openrowset command in SQL Server. Here is some sample usage of the Stored proc

DECLARE @SQL_SP1 VARCHAR(MAX)
DECLARE @SQL_SP2 VARCHAR(MAX)

-- Compare results of 2 Stored Procs
SET @SQL_SP1 = 'EXEC SomeDB.dbo.[usp_GetWithTheProgram_OLD] 100, ''SomeParamX'''
SET @SQL_SP1 = 'EXEC SomeDB.dbo.[usp_GetWithTheProgram_NEW] 50, ''SomeParamX'''
EXEC utlCompareStatementResults @SQL_SP1, @SQL_SP2

-- Compare just 2 SQL Statements
SET @SQL_SP1 = 'SELECT * FROM SomeDB.dbo.Table1 WHERE CreatedOn > ''2016-05-08'''
SET @SQL_SP1 = 'SELECT * FROM SomeDB.dbo.Table1 WHERE CreatedOn > ''2016-06-11'''
EXEC utlCompareStatementResults @SQL_SP1, @SQL_SP2

The SP requires the following prerequisites, which may not be ideal for a production environment, but very useful for local QA, DEV and Test environments. It uses openrowset in the code.

EXEC sp_configure 'show advanced options', 1
EXEC sp_configure 'ad hoc distributed queries', 1
EXEC sp_serveroption @@SERVERNAME, 'DATA ACCESS', TRUE

Here is the code for the stored proc.

==================================================================================
    --== SUMMARY utlCompareStatementResults
    --==    - requires sp_configure 'show advanced options', 1
    --==    - requires sp_configure 'ad hoc distributed queries', 1
    --==    - maybe requires EXEC sp_serveroption @@SERVERNAME, 'DATA ACCESS', TRUE
    --==    - requires the RecordSet Output to have Unique ColumnNames (no duplicate columns)
    --==    - requires references in straight SQL to be fully qualified [dbname].[schema].[objects] but not within an SP
    --==    - requires references SP call to be fully qualifed [dbname].[schema].[spname] but not objects with the SP
    --== OUTPUT
    --==    Differences are returned 
    --==    If there is no recordset returned, then theres no differences
    --==    However if you are comparing 2 empty recordsets, it doesn't mean anything
    --== USAGE
    --==   DECLARE @SQL_SP1 VARCHAR(MAX)
    --==   DECLARE @SQL_SP2 VARCHAR(MAX)
    --==   -- Compare just 2 SQL Statements
    --==   SET @SQL_SP1 = 'SELECT * FROM SomeDB.dbo.Table1 WHERE CreatedOn > ''2016-05-08'''
    --==   SET @SQL_SP1 = 'SELECT * FROM SomeDB.dbo.Table1 WHERE CreatedOn > ''2016-06-11'''
    --==   EXEC utlCompareStatementResults @SQL_SP1, @SQL_SP2
    --==
    --==   -- Compare results of 2 Stored Procs
    --==   SET @SQL_SP1 = 'EXEC SomeDB.dbo.[usp_GetWithTheProgram_OLD] 100, ''SomeParamX'''
    --==   SET @SQL_SP1 = 'EXEC SomeDB.dbo.[usp_GetWithTheProgram_NEW] 50, ''SomeParamX'''
    --==   EXEC utlCompareStatementResults @SQL_SP1, @SQL_SP2
    --==================================================================================
    CREATE PROCEDURE utlCompareStatementResults
       @SQL_SP1 VARCHAR(MAX),
       @SQL_SP2 VARCHAR(MAX)
    AS
    BEGIN
        DECLARE @TABLE1 VARCHAR(200)
        DECLARE @TABLE2 VARCHAR(200)
        DECLARE @SQL_OPENROWSET VARCHAR(MAX) 
        DECLARE @CONNECTION VARCHAR(100)

        SET @CONNECTION = 'server='+@@SERVERNAME+';Trusted_Connection=yes'

        SET @SQL_SP1 = REPLACE(@SQL_SP1, '''','''''')
        SET @SQL_SP2 = REPLACE(@SQL_SP2, '''','''''')

        SET @TABLE1 = '#' + SUBSTRING(CONVERT(VARCHAR(250),NEWID()), 1, 8)
        SET @TABLE2 = '#' + SUBSTRING(CONVERT(VARCHAR(250),NEWID()), 1, 8)

        SET @SQL_OPENROWSET =
        'SELECT * ' + ' ' +
        'INTO ' + @TABLE1 + ' ' +
        'FROM OPENROWSET(''SQLNCLI'', ' + '''' + @CONNECTION + '''' +
                        ',''' + @SQL_SP1 +'''); ' +
        'SELECT * ' + ' ' +
        'INTO ' + @TABLE2 + ' ' +
        'FROM OPENROWSET(''SQLNCLI'', ' + '''' + @CONNECTION + '''' +
                        ',''' + @SQL_SP2 +'''); ' +
        '(SELECT * FROM ' + @TABLE1 + ' EXCEPT SELECT * FROM ' + @TABLE2 + ') '  +
        ' UNION ALL ' +
        '(SELECT * FROM ' + @TABLE2 + ' EXCEPT SELECT * FROM ' + @TABLE1 + '); ' +
        'DROP TABLE ' + @TABLE1 + '; ' +
        'DROP TABLE ' + @TABLE2 + '; '
        PRINT @SQL_OPENROWSET
        EXEC (@SQL_OPENROWSET)
        PRINT 'DifferenceCount: ' + CONVERT(VARCHAR(100), @@ROWCOUNT)
    END

score 2 · Answer 4 · answered Jun 13 '12 at 15:06

2

create table #OldProcResults (
    <Blah>
)

create table #NewProcResults (
    <Blih>
)

insert into #OldProcResults
    exec MyOldProc

insert into #NewProcResults
    exec MyNewProc

then use Jabs' answer to compare the two tables.

answered Jun 13 '12 at 15:06

David Brabant

41,623
16
83
111

score 2 · Answer 5 · answered Apr 26 '19 at 09:06

EXCEPT is the key to compare two querys (as @jabs said).

SELECT count(*), * FROM "query 1 here"
EXCEPT
SELECT count(*), * FROM "query 2 here"

Adding count(*) for each query to make sure both have the same results. Just in case there are some repeated rows which are deleted by except.

score 0 · Answer 6 · answered Jun 13 '12 at 14:59

0

create two temp tables, one for each procedure. run the procedure to insert rows into the appropriate table.

then select * from one MINUS select * from the other and visa-versa

answered Jun 13 '12 at 14:59

Randy

16,480
1
37
55

MINUS is an Oracle statement, EXCEPT (as in above examples) is the T-SQL equivalent – flash May 22 '15 at 11:12

score 0 · Answer 7 · answered Sep 26 '21 at 18:32

Here some more verbose aproach that helped me while studying the matter on MSSQL. @tpvasconcelos´s answer is just the most correct so far.

DECLARE @AAA TABLE(id bigint NOT NULL) 
    INSERT INTO @AAA
    VALUES (1),(2),(3),(4),(5),(6),(7)

DECLARE @bbb TABLE(id bigint NOT NULL)
    INSERT INTO @bbb
    VALUES (1),(2),(3),(4),(5),(6),(7)

Declare @diff int = (SELECT COUNT(*) FROM (SELECT * FROM @AAA EXCEPT SELECT * FROM @bbb) AS TB)


Declare @aux1 int;
set @aux1 = (select count(*) from @BBB);

Declare @aux2 int;
set @aux2 = (SELECT COUNT(*)  FROM @AAA)

Declare @aux3 int;
set @aux3 = (SELECT COUNT(*) FROM (select * from @AAA union SELECT * FROM @bbb) as tb);  -- for union to work it needs a alias


IF @diff <> 0
    begin
        PRINT 'Flow @flows_name has failed.'
    end
else
    begin
        IF @aux1 = @aux3
            begin
                PRINT 'Flow @flows_name might have SUCCEEDED!'
            end
        else
            begin
                PRINT 'Flow @flows_name has failed.'
            end
    end

score 0 · Answer 8 · edited Aug 13 '22 at 09:06

0

I found this query works the best in T-SQL to compare two queries and to know which table the results are coming from

WITH CTE AS
 (SELECT insert query 1

EXCEPT

SELECT insert query 2)

SELECT insert query 2, 'a'

EXCEPT

SELECT insert query 1, 'a'

UNION ALL

SELECT *, 'b'  FROM cte

edited Aug 13 '22 at 09:06

Jan

4,974
3
26
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answered Aug 08 '22 at 21:11

AD415

1
1

SQL Server compare results of two queries that should be identical

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