SQL “if exists…” dynamic query

Question

Suppose I have a query stored in a variable like this (it\'s actually dynamically populated and more complex, but this is for demonstration purposes):

DECLAR         


        

Answer 1

Hi I think that only way is to put IF EXISTS part into code of execution. My case is to stop execution in point when select affects at least one row, that is goal of IF EXISTS.

Little example that saves reading all records covering by condition to first occurence:

set nocount off;
drop table if exists #temp
go
create table #temp (idCol int identity(1,1),someText nvarchar(1))
go
insert into #temp values ('a')
go 25000

declare @query nvarchar(max)
,@resultFork bit
set @query = 'if exists (select * from #temp where idCol % 3 = 0)
    set @resultFork=1
    else
    set @resultFork=0'
print @query
exec sp_executeSQL @query, N'@resultFork int output', @resultFork=@resultFork output
print @resultFork
/*Now U can use @resultFork in simple if condition...
if @resultFork = 1 
begin
    --
end
else 
begin
    --
end
*/