Get ROWCOUNT from INSTEAD OF TRIGGER

Question

A legacy app does an INSERT on a table with an instead of trigger and subsequently uses the rowcount for further processing.

We now need to opt out of certain INSERTs with the use of an INSTEAD OF INSERT trigger.

The problem is that @@ROWCOUNT still returns the number of attempted inserts.

For example, a fictitious trigger that will never complete an insert might be

ALTER TRIGGER [dbo].[trig_ACCOUNT_CREDITS_RunningTotalINSERT]
   ON  [dbo].[ACCOUNT_CREDITS] 
   INSTEAD OF INSERT
AS 
BEGIN
 --tried with NOCOUNT ON and OFF
 SET NOCOUNT OFF;

 --This is an example of the branching logic that might determine 
 --whether or not to do the INSERT
IF 1=2 --no insert will ever occur (example only)
BEGIN
    INSERT INTO dbo.ACCOUNT_CREDITS (COL1, COL2)
    SELECT COL1, COL2 from INSERTED
END
END

and some INSERT statements might be

--No rows will be inserted because value of COL1 < 5
INSERT INTO dbo.ACCOUNT_CREDITS (COL1, COL2) VALUES ( 3, 3)

--We would assume row count to be 0, but returns 1
select @@ROWCOUNT

--No rows will be inserted because value of COL1 < 5       
INSERT INTO dbo.ACCOUNT_CREDITS (COL1, COL2) 
SELECT 1, 1
union all
SELECT 2, 2

--We would assume row count to be 0, but returns 2
select @@ROWCOUNT

I can work around the issue, but it bothers me that I can't trust @@ROWCOUNT. I can find no reference to this issue on SO or those other knowledge banks. Is this simply a case of TRIGGERS ARE EVIL?

Can I affect @@ROWCOUNT?

Answer 1

Some statements may change @@ROWCOUNT inside the trigger.

Statement

SELECT * FROM INSERTED WHERE COL1 < 5

executes and set @@ROWCOUNT to 1

Put statement

SET NOCOUNT ON;

then

IF NOT EXISTS (SELECT * FROM INSERTED WHERE COL1 < 5)
BEGIN
    SET NOCOUNT OFF;

    INSERT INTO dbo.ACCOUNT_CREDITS (COL1, COL2)
    SELECT COL1, COL2 from INSERTED
END