SQL WHERE.. IN clause multiple columns

Question

I need to implement the following query in SQL Server:

select *
from table1
WHERE  (CM_PLAN_ID,Individual_ID)
IN
(
 Select CM_PLAN_ID, Individual_ID
 From CR         


        

Answer 1

A simple EXISTS clause is cleanest

select *
from table1 t1
WHERE
EXISTS
(
 Select * --or 1. No difference...
 From CRM_VCM_CURRENT_LEAD_STATUS Ex
 Where Lead_Key = :_Lead_Key
-- correlation here...
AND
t1.CM_PLAN_ID = Ex.CM_PLAN_ID AND t1.CM_PLAN_ID =  Ex.Individual_ID
)

If you have multiple rows in the correlation then a JOIN gives multiple rows in the output, so you'd need distinct. Which usually makes the EXISTS more efficient.

Note SELECT * with a JOIN would also include columns from the row limiting tables