Select data, setting a calculated value into a column
I'm selecting data from a table within a trigger (FOR UPDATE). Some rows I'm selecting h开发者_如何学编程ave been updated by a transaction, that initiated the trigger, and some rows are not. I'd like to write somewhere in the dataset a flag for every row, which value would be calculated as "id IN (SELECT [id] FROM INSERTED)". This flag would show, is a row updated with the last transaction or not.
Is it possible in SQL?
Sure, I can do 2 separate queries, with 2 different conditions, but the trigger perfomance is real bottleneck...
Here's an example for SQL Server:
if object_id('TriggerTest') is not null
drop table TriggerTest
create table TriggerTest (id int identity, name varchar(50), inLastUpdate bit)
insert TriggerTest (name) values ('joe'), ('barrack'), ('george'), ('dick')
go
create trigger dbo.TriggerTestDelete
on TriggerTest
after update
as begin
declare @date datetime
set @date = GETDATE()
update dbo.TriggerTest
set inLastUpdate =
case when id in (select id from inserted) then 1
else 0
end
end
go
update TriggerTest set name = name where id in (1,2)
update TriggerTest set name = name where id in (1,3)
select * from TriggerTest
This prints:
id name inLastUpdate
1 joe 1
2 barrack 0
3 george 1
4 dick 0
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