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 r

Answer 1

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.

Answer 2

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

Answer 3

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

Answer 4

To complete @jabs answer, you can use the following template to get the difference between two queries:

WITH q1 AS (<INSERT_QUERY_1_HERE>)
   , q2 AS (<INSERT_QUERY_2_HERE>)
SELECT * FROM q1 EXCEPT SELECT * FROM q2
UNION ALL (
SELECT * FROM q2 EXCEPT SELECT * FROM q1);

---

Example 1: This returns 0 rows, as the queries are identical

WITH q1 AS (SELECT * FROM my_table)
   , q2 AS (SELECT * FROM my_table)
SELECT * FROM q1 EXCEPT SELECT * FROM q2
UNION ALL (
SELECT * FROM q2 EXCEPT SELECT * FROM q1);

Example 2: This returns the different rows between the queries (where foo = 'bar')

WITH q1 AS (SELECT * FROM my_table)
   , q2 AS (SELECT * FROM my_table WHERE foo <> 'bar')
SELECT * FROM q1 EXCEPT SELECT * FROM q2
UNION ALL (
SELECT * FROM q2 EXCEPT SELECT * FROM q1);

Example 3: Just for fun, you can check that the query in Example 2 is identical to queries the rows where foo = 'bar'.

WITH q1 AS (

    WITH q1 AS (SELECT * FROM my_table)
       , q2 AS (SELECT * FROM my_table WHERE foo <> 'bar')
    SELECT * FROM q1 EXCEPT SELECT * FROM q2
    UNION ALL (
    SELECT * FROM q2 EXCEPT SELECT * FROM q1)

)
   , q2 AS (SELECT * FROM my_table WHERE foo = 'bar')
SELECT * FROM q1 EXCEPT SELECT * FROM q2
UNION ALL (
SELECT * FROM q2 EXCEPT SELECT * FROM q1);

Answer 5

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.

Answer 6

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