Update if exist in other table I want to update column in table A if the value of column A1 exist in one column of B table for example B2

update A
set A1 = 'F'
WHERE  A1 in (SELECT B2 FROM B );


I tried somethig like this but no success, i tried too with exists
It may not be the most efficient method but I can't see a problem with your SQL.

Recommend you check your data..