Question

I have a fairly complex SP (logic wise) with nested IF BEGIN END ELSE, there are multiple end points in this nested logic where the logic fails and I RAISERROR and two places that result in success and SQL being actioned.

How, at the end of the SP can I trap the errors and do a IF Error Count>0 THEN ROLLBACK

DECLARE @errCount int=0
DECLARE @DataSetCount int=0
DECLARE @countCurrent int=0
DECLARE @countHistorical int=0


IF (isnumeric(@DataSetID)=(0) OR @DataSetID=(0)) 
BEGIN
    RAISERROR('The DataSet specfied does not appear to be valid', 5, 1)
END
ELSE
IF  (@Destination='C' OR @Destination='H') 
    BEGIN
        if Exists (SELECT NULL from tblOpportunityDataSets where DataSetID=@DataSetID)
        BEGIN
            SET @countCurrent=(SELECT COUNT(1) from tblOptyRecordsCurrent where DataSetID=@DataSetID)
            SET @countHistorical=(SELECT COUNT(1) from tblOptyRecordsHistorical where DataSetID=@DataSetID)
            IF @destination='C'
            BEGIN
                if @countCurrent>0 
                BEGIN
                    RAISERROR('There are already existing records in the Current Tables for the specified DataSet', 5, 1)
                END ELSE
                if @countHistorical=0 
                BEGIN
                    RAISERROR('There do not appear to be any records in the Historical Tables to transfer for the specified Dataset', 5, 1)
                END ELSE
                BEGIN
                    -- ENTER TRANSFER CODE
                    INSERT INTO tblRecordsHistorical
                    ( X, Y, Z ) 
                    SELECT X, Y, Z  FROM tblA
                    WHERE x=y
                    -- Check that record count in both tables match
                    SET @countCurrent=(SELECT COUNT(1) from tblOptyRecordsCurrent where DataSetID=@DataSetID)
                    SET @countHistorical=(SELECT COUNT(1) from tblOptyRecordsHistorical where DataSetID=@DataSetID)
                    IF (@countCurrent<>@countHistorical)
                    BEGIN
                        RAISERROR('There was an error whilst copying the records into the Historical Tables, Source and Destination Record Count do not match', 5, 1)
                    END ELSE
                    BEGIN


                    END
                END
            END ELSE
            IF @Destination='H'
            BEGIN
                if @countHistorical>0 
                BEGIN
                    RAISERROR('There are already existing records in the Historical Tables for the specified DataSet', 5, 1)
                END ELSE
                if @countCurrent=0 
                BEGIN
                    RAISERROR('There do not appear to be any records in the Historical Tables to transfer for the specified Dataset', 5, 1)
                END ELSE
                BEGIN
                    RAISERROR('DataSet Found, ready to transfer records to HISTORICAL', 5, 1)       
                    -- ENTER TRANSFER CODE
                    INSERT INTO tblOptyRecordsCurrent
                    ( X, Y, Z ) 
                    SELECT X, Y, Z  FROM tblB
                    WHERE x=y
                    -- Check that record count in both tables match
                    SET @countCurrent=(SELECT COUNT(1) from tblOptyRecordsCurrent where DataSetID=@DataSetID)
                    SET @countHistorical=(SELECT COUNT(1) from tblOptyRecordsHistorical where DataSetID=@DataSetID)



                END
            END
        END
        ELSE
        BEGIN
            RAISERROR('The DataSet you have specified cannot be found', 5, 1)
        END
    END
    ELSE
    BEGIN
        RAISERROR('You have not specified a valid Destination', 5, 1)
    END

Note that in the two sections that contain the INSERT INTO code, there will be at least two additional SQL Action Statements, which must all work or they all fail.

EDIT: I’ve gone with

BEGIN TRAN
BEGIN TRY
    -- STATEMENT 1
    INSERT INTO X WHERE Y
    -- STATEMENT 2
    DELETE FROM X WHERE Y
    -- STATEMENT 3
    UPDATE X WHERE Y
    COMMIT
END TRY
BEGIN CATCH
    ROLLBACK TRAN
    RAISERROR('There was an error whilst copying the records into the Current Tables.  The Transaction has been rolled back', 5, 1)
END CATCH                               

Answer 1

In order to be able to do a rollback, you need to do a begin transaction at the start.

Then you either commit or rollback the actions.

http://msdn.microsoft.com/en-us/library/ms174377

You may find the try/catch syntax easier

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