SQL insert trigger to catch NULL values for mutiple rows - sql-server

Question

I have written the trigger below that prevents from NULL being entered in the pch_x field . It works fine if i insert 1 row but doesnt work if I enter more than one at once . Could someone please help me out a little ? Here is my code
create trigger test
ON [dbo].TEMP
for INSERT
AS
BEGIN
declare #xcheck varchar(50)
set #xcheck= (select i.pch_x FROM temp L INNER JOIN INSERTED I
ON L.id = I.id)
F (#xcheck is NULL )
begin
RAISERROR('NULL in pch_x', 16, 1)
ROLLBACK
end
END

Answer 1

I'm not sure why you're doing this in a trigger, but the set based way to do this test would be to use EXISTS:
create trigger test
ON [dbo].TEMP
for INSERT
AS
BEGIN
IF EXISTS(select * FROM temp L INNER JOIN
INSERTED I
ON L.id = I.id
where i.pch_x IS NULL)
begin
RAISERROR('NULL in pch_x', 16, 1)
ROLLBACK
end
END
I'm also not sure why you're joining back to the table - I'd have thought the check could run without reference to temp:
create trigger test
ON [dbo].TEMP
for INSERT
AS
BEGIN
IF EXISTS(select * FROM INSERTED
where pch_x IS NULL)
begin
RAISERROR('NULL in pch_x', 16, 1)
ROLLBACK
end
END
For you unusual requirement that, in a rowset containing some rows with nulls, you want success for those rows without nulls and failure for those rows with nulls, most sensible would be an INSTEAD OF trigger:
create trigger test
ON [dbo].TEMP
INSTEAD OF INSERT
AS
BEGIN
declare #rc int
INSERT INTO dbo.temp (/* column list */)
SELECT /* column list */ from inserted where pch_x IS NOT NULL
set #rc = ##ROWCOUNT
IF #rc <> (select COUNT(*) from inserted)
begin
RAISERROR('NULL in pch_x', 16, 1)
--ROLLBACK
end
END