Question

i have two table:

declare @t1 table (id int)
declare @t2 table (id int)


insert into @t1
select 1 union select 3 union select 7

insert into @t2
select 1 union select 3 union select 7 union select 9 union select 4

select count(*) from @t1 t inner join @t2 t1 on t.id = t1.id

i get the result for above query as 3. i need true or false if all the records in t1 exists in t2.

this is a simplified example of the real table structure. the real tables may have millions of records, so please let me know some optimized way of doing it

Answer 1

SELECT CASE 
         WHEN EXISTS (SELECT id 
                      FROM   @t1 
                      EXCEPT 
                      SELECT id 
                      FROM   @t2) THEN 0 
         ELSE 1 
       END