I have data as below :
DISTNAME DLIBSEQN LIB_DEVT GLIBSEQN GRID
???????? ???????? xxxxxxx
yyyyyyyy B2797 3584-L22
zzzzzzzz 10000 GRID
1001A 10000
1001A 10000
1001A 10000
10015 10000
10015 10000
So based on the DLIBSEQN variable value if it match with GLIBSEQN variable value for all observation it should update the GRID value with the name of the DISTNNAME found from first record where we have zzzzzz ....