TSQL - How to use GO inside of a BEGIN .. END block? - sql

Question

I am generating a script for automatically migrating changes from multiple development databases to staging/production. Basically, it takes a bunch of change-scripts, and merges them into a single script, wrapping each script in a IF whatever BEGIN ... END statement.
However, some of the scripts require a GO statement so that, for instance, the SQL parser knows about a new column after it's created.
ALTER TABLE dbo.EMPLOYEE
ADD COLUMN EMP_IS_ADMIN BIT NOT NULL
GO -- Necessary, or next line will generate "Unknown column: EMP_IS_ADMIN"
UPDATE dbo.EMPLOYEE SET EMP_IS_ADMIN = whatever
However, once I wrap that in an IF block:
IF whatever
BEGIN
ALTER TABLE dbo.EMPLOYEE ADD COLUMN EMP_IS_ADMIN BIT NOT NULL
GO
UPDATE dbo.EMPLOYEE SET EMP_IS_ADMIN = whatever
END
It fails because I am sending a BEGIN with no matching END. However, if I remove the GO it complains again about an unknown column.
Is there any way to create and update the same column within a single IF block?

Answer 1

I had the same problem and finally managed to solve it using SET NOEXEC.
IF not whatever
BEGIN
SET NOEXEC ON;
END
ALTER TABLE dbo.EMPLOYEE ADD COLUMN EMP_IS_ADMIN BIT NOT NULL
GO
UPDATE dbo.EMPLOYEE SET EMP_IS_ADMIN = whatever
SET NOEXEC OFF;

Answer 2

GO is not SQL - it is simply a batch separator used in some MS SQL tools.
If you don't use that, you need to ensure the statements are executed separately - either in different batches or by using dynamic SQL for the population (thanks #gbn):
IF whatever
BEGIN
ALTER TABLE dbo.EMPLOYEE ADD COLUMN EMP_IS_ADMIN BIT NOT NULL;
EXEC ('UPDATE dbo.EMPLOYEE SET EMP_IS_ADMIN = whatever')
END

Answer 3

You could try sp_executesql, splitting the contents between each GO statement into a separate string to be executed, as demonstrated in the example below. Also, there is a #statementNo variable to track which statement is being executed for easy debugging where an exception occurred. The line numbers will be relative to the beginning of the relevant statement number that caused the error.
BEGIN TRAN
DECLARE #statementNo INT
BEGIN TRY
IF 1=1
BEGIN
SET #statementNo = 1
EXEC sp_executesql
N' ALTER TABLE dbo.EMPLOYEE
ADD COLUMN EMP_IS_ADMIN BIT NOT NULL'
SET #statementNo = 2
EXEC sp_executesql
N' UPDATE dbo.EMPLOYEE
SET EMP_IS_ADMIN = 1'
SET #statementNo = 3
EXEC sp_executesql
N' UPDATE dbo.EMPLOYEE
SET EMP_IS_ADMIN = 1x'
END
END TRY
BEGIN CATCH
PRINT 'Error occurred on line ' + cast(ERROR_LINE() as varchar(10))
+ ' of ' + 'statement # ' + cast(#statementNo as varchar(10))
+ ': ' + ERROR_MESSAGE()
-- error occurred, so rollback the transaction
ROLLBACK
END CATCH
-- if we were successful, we should still have a transaction, so commit it
IF ##TRANCOUNT > 0
COMMIT
You can also easily execute multi-line statements, as demonstrated in the example above, by simply wrapping them in single quotes ('). Don't forget to escape any single quotes contained inside the string with a double single-quote ('') when generating the scripts.

Answer 4

You can enclose the statements in BEGIN and END instead of the GO inbetween
IF COL_LENGTH('Employees','EMP_IS_ADMIN') IS NULL --Column does not exist
BEGIN
BEGIN
ALTER TABLE dbo.Employees ADD EMP_IS_ADMIN BIT
END
BEGIN
UPDATE EMPLOYEES SET EMP_IS_ADMIN = 0
END
END
(Tested on Northwind database)
Edit: (Probably tested on SQL2012)

Answer 5

I ultimately got it to work by replacing every instance of GO on its own line with
END
GO
---Automatic replacement of GO keyword, need to recheck IF conditional:
IF whatever
BEGIN
This is greatly preferable to wrapping every group of statements in a string, but is still far from ideal. If anyone finds a better solution, post it and I'll accept it instead.

Answer 6

You may try this solution:
if exists(
SELECT...
)
BEGIN
PRINT 'NOT RUN'
RETURN
END
--if upper code not true
ALTER...
GO
UPDATE...
GO

Answer 7

I have used RAISERROR in the past for this
IF NOT whatever BEGIN
RAISERROR('YOU''RE ALL SET, and sorry for the error!', 20, -1) WITH LOG
END
ALTER TABLE dbo.EMPLOYEE ADD COLUMN EMP_IS_ADMIN BIT NOT NULL
GO
UPDATE dbo.EMPLOYEE SET EMP_IS_ADMIN = whatever

Answer 8

You can incorporate a GOTO and LABEL statements to skip over code, thus leaving the GO keywords intact.