Question

I need to know if all rows from one table exists in other:

declare @Table1 table (id int)
declare @Table2 table (id int)

insert into @Table1(id) values (1)
insert into @Table1(id) values (4)
insert into @Table1(id) values (5)


insert into @Table2(id) values (1)
insert into @Table2(id) values (2)
insert into @Table2(id) values (3)

if exists (select id from @Table1 where id in (select id from @Table2))
    select 'yes exists'
else
    select 'no, doesn''t exist' 

This query returns yes exists but should return no, doesn't exist because only 1 exists in @Table2, values 4 and 5 don’t.

What should I change in my query? Thanks!

Answer 1

IF NOT EXISTS (
    SELECT ID FROM @Table1
    EXCEPT
    SELECT ID FROM @Table2
)
SELECT 'yes exists'
ELSE SELECT 'no, doesn''t exist'