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

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