[sql] SQL Server - stop or break execution of a SQL script

Is there a way to immediately stop execution of a SQL script in SQL server, like a "break" or "exit" command?

I have a script that does some validation and lookups before it starts doing inserts, and I want it to stop if any of the validations or lookups fail.

I would not use RAISERROR- SQL has IF statements that can be used for this purpose. Do your validation and lookups and set local variables, then use the value of the variables in IF statements to make the inserts conditional.

You wouldn't need to check a variable result of every validation test. You could usually do this with only one flag variable to confirm all conditions passed:

declare @valid bit

set @valid = 1

if -- Condition(s)
begin
  print 'Condition(s) failed.'
  set @valid = 0
end

-- Additional validation with similar structure

-- Final check that validation passed
if @valid = 1
begin
  print 'Validation succeeded.'

  -- Do work
end

Even if your validation is more complex, you should only need a few flag variables to include in your final check(s).

Enclose it in a try catch block, then the execution will be transfered to catch.

BEGIN TRY
    PRINT 'This will be printed'
    RAISERROR ('Custom Exception', 16, 1);
    PRINT 'This will not be printed'
END TRY
BEGIN CATCH
    PRINT 'This will be printed 2nd'
END CATCH;

Back in the day we used the following...worked best:

RAISERROR ('Error! Connection dead', 20, 127) WITH LOG

None of these works with 'GO' statements. In this code, regardless of whether the severity is 10 or 11, you get the final PRINT statement.

Test Script:

-- =================================
PRINT 'Start Test 1 - RAISERROR'

IF 1 = 1 BEGIN
    RAISERROR('Error 1, level 11', 11, 1)
    RETURN
END

IF 1 = 1 BEGIN
    RAISERROR('Error 2, level 11', 11, 1)
    RETURN
END
GO

PRINT 'Test 1 - After GO'
GO

-- =================================
PRINT 'Start Test 2 - Try/Catch'

BEGIN TRY
    SELECT (1 / 0) AS CauseError
END TRY
BEGIN CATCH
    SELECT ERROR_MESSAGE() AS ErrorMessage
    RAISERROR('Error in TRY, level 11', 11, 1)
    RETURN
END CATCH
GO

PRINT 'Test 2 - After GO'
GO

Results:

Start Test 1 - RAISERROR
Msg 50000, Level 11, State 1, Line 5
Error 1, level 11
Test 1 - After GO
Start Test 2 - Try/Catch
 CauseError
-----------

ErrorMessage
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Divide by zero error encountered.

Msg 50000, Level 11, State 1, Line 10
Error in TRY, level 11
Test 2 - After GO

The only way to make this work is to write the script without GO statements. Sometimes that's easy. Sometimes it's quite difficult. (Use something like IF @error <> 0 BEGIN ....)

I would suggest that you wrap your appropriate code block in a try catch block. You can then use the Raiserror event with a severity of 11 in order to break to the catch block if you wish. If you just want to raiserrors but continue execution within the try block then use a lower severity.

Make sense?

Cheers, John

[Edited to include BOL Reference]

http://msdn.microsoft.com/en-us/library/ms175976(SQL.90).aspx

Further refinig Sglasses method, the above lines force the use of SQLCMD mode, and either treminates the scirpt if not using SQLCMD mode or uses :on error exit to exit on any error
CONTEXT_INFO is used to keep track of the state.

SET CONTEXT_INFO  0x1 --Just to make sure everything's ok
GO 
--treminate the script on any error. (Requires SQLCMD mode)
:on error exit 
--If not in SQLCMD mode the above line will generate an error, so the next line won't hit
SET CONTEXT_INFO 0x2
GO
--make sure to use SQLCMD mode ( :on error needs that)
IF CONTEXT_INFO()<>0x2 
BEGIN
    SELECT CONTEXT_INFO()
    SELECT 'This script must be run in SQLCMD mode! (To enable it go to (Management Studio) Query->SQLCMD mode)\nPlease abort the script!'
    RAISERROR('This script must be run in SQLCMD mode! (To enable it go to (Management Studio) Query->SQLCMD mode)\nPlease abort the script!',16,1) WITH NOWAIT 
    WAITFOR DELAY '02:00'; --wait for the user to read the message, and terminate the script manually
END
GO

----------------------------------------------------------------------------------
----THE ACTUAL SCRIPT BEGINS HERE-------------

If you can use SQLCMD mode, then the incantation

:on error exit

(INCLUDING the colon) will cause RAISERROR to actually stop the script. E.g.,

:on error exit

IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[SOMETABLE]') AND type in (N'U')) 
    RaisError ('This is not a Valid Instance Database', 15, 10)
GO

print 'Keep Working'

will output:

Msg 50000, Level 15, State 10, Line 3
This is not a Valid Instance Database
** An error was encountered during execution of batch. Exiting.

and the batch will stop. If SQLCMD mode isn't turned on, you'll get parse error about the colon. Unfortuantely, it's not completely bulletproof as if the script is run without being in SQLCMD mode, SQL Managment Studio breezes right past even parse time errors! Still, if you're running them from the command line, this is fine.

You can alter the flow of execution using GOTO statements:

IF @ValidationResult = 0
BEGIN
    PRINT 'Validation fault.'
    GOTO EndScript
END

/* our code */

EndScript:

I use RETURN here all the time, works in script or Stored Procedure

Make sure you ROLLBACK the transaction if you are in one, otherwise RETURN immediately will result in an open uncommitted transaction

Just use a RETURN (it will work both inside and outside a stored procedure).

This was my solution:

...

BEGIN
    raiserror('Invalid database', 15, 10)
    rollback transaction
    return
END

In SQL 2012+, you can use THROW.

THROW 51000, 'Stopping execution because validation failed.', 0;
PRINT 'Still Executing'; -- This doesn't execute with THROW

From MSDN:

Raises an exception and transfers execution to a CATCH block of a TRY…CATCH construct ... If a TRY…CATCH construct is not available, the session is ended. The line number and procedure where the exception is raised are set. The severity is set to 16.

Thx for the answer!

raiserror() works fine but you shouldn't forget the return statement otherwise the script continues without error! (hense the raiserror isn't a "throwerror" ;-)) and of course doing a rollback if necessary!

raiserror() is nice to tell the person who executes the script that something went wrong.

If you are simply executing a script in Management Studio, and want to stop execution or rollback transaction (if used) on first error, then the best way I reckon is to use try catch block (SQL 2005 onward). This works well in Management studio if you are executing a script file. Stored proc can always use this as well.

I extended the noexec on/off solution successfully with a transaction to run the script in an all or nothing manner.

set noexec off

begin transaction
go

<First batch, do something here>
go
if @@error != 0 set noexec on;

<Second batch, do something here>
go
if @@error != 0 set noexec on;

<... etc>

declare @finished bit;
set @finished = 1;

SET noexec off;

IF @finished = 1
BEGIN
    PRINT 'Committing changes'
    COMMIT TRANSACTION
END
ELSE
BEGIN
    PRINT 'Errors occured. Rolling back changes'
    ROLLBACK TRANSACTION
END

Apparently the compiler "understands" the @finished variable in the IF, even if there was an error and the execution was disabled. However, the value is set to 1 only if the execution was not disabled. Hence I can nicely commit or rollback the transaction accordingly.

you could wrap your SQL statement in a WHILE loop and use BREAK if needed

WHILE 1 = 1
BEGIN
   -- Do work here
   -- If you need to stop execution then use a BREAK


    BREAK; --Make sure to have this break at the end to prevent infinite loop
END

You can use GOTO statement. Try this. This is use full for you.

WHILE(@N <= @Count)
BEGIN
    GOTO FinalStateMent;
END

FinalStatement:
     Select @CoumnName from TableName

Is this a stored procedure? If so, I think you could just do a Return, such as "Return NULL";

you can use RAISERROR.