update field where two tables match

[me55]

i know this is fairly similar to other posts but i am just missing something about getting this to work right.  so i have two tables, a and b with fields that match, 1, 2, 3, 4.  so i need to get a field in a to Y on an inner join to table b.  i know sql really well but am new to sas and i am using eg. 

so, if fields 1, 2, 3, and 4 match between the two tables it needs to set a.z='Y'...

[me55 · Accepted solution]

i think i solved my own problem.  here is the code i am using...

proc sql;
update  a
    set a.z='Y'
    where exists
        (select * from b
            where a.1=b.1 and a.2=b.2 and a.3=b.3
            and a.4=b.4);

i havent checked it but i believe this works well and gets what i need it to. 

thanks...