Question

I have two tables.

• TableA (ID int, Match1 char, Match2 char, status char)
• TableB (Match1 char, match2)

I want to flag rows in tableA as fail in status where for same match1, match2 do not exist in tableB.

Example:

TableA

ID Match1 Match2 Status
1   100    AB    
2   100    AR
3   200    BC
4   200    VB
5   200    AB

TableB

Match1 Match2
100     AF
100     AR
100     BG
200     AB
200     BJ
200     VB

Expected result:

TableA

ID Match1 Match2 Status
1   100    AB    FAIL 
2   100    AR    NULL
3   200    BC    FAIL
4   200    VB    NULL
5   200    AB    NULL

Thanks

I used(not working):

Update A
set status = 'FAIL'
from TableA A
  Inner join TableB B
  ON A.match1 = B.match1
  WHERE A.match2 <> B.Match2

Answer 1

UPDATE a
    SET status = 'FAIL'
    FROM TableA a
    WHERE NOT EXISTS(SELECT NULL
                         FROM TableB b
                         WHERE a.match1 = b.match1
                             AND a.match2 = b.match2)