SQL Server query help needed

Question

When I try the following query, zero rows are affected. Can someone help me to fix this?

UPDATE PLAN 
SET PLANID = (SELECT PLANID FROM MODE WHERE [NAME]='Sam')
WHERE CUSTOMERID IN (SELECT CUSTOMERID FROM ENTITYCUSTOMER WHERE EMPID = 707)

(SELECT PLANID FROM MODE WHERE [NAME]='Sam') will return a single code

(SELECT CUSTOMERID FROM ENTITYCUSTOMER WHERE EMPID = 707) may return multiple values.

Please help need a solution for this. Thanks

Answer 1

SELECT PLANID FROM MODE WHERE [NAME]='Sam'

The 'MODE' table must not be keyed on PLANID; so it can't bind a specific value to the update. One option is to create a cursor, and read the correct value with which to update. Another is to do this in whatever client code language you are using (presumably a .net langugage?)