Igor, Please review the attached patch for LP BUG#641203 we discussed last week. Since there was no email service, the commit mail didn't get through, so the commit comment is: " Fixed LP BUG#641203: Query returns rows where no result is expected (impossible WHERE) The cause for the bug was two-fold: 1. Incorrect detection of whether a table is the first one in a query plan - "used_table & 1" actually checks if used_table is table with number "1". 2. Missing logic to delay the evaluation of (expensive) constant conditions during the execution phase. The fix adds/changes: The patch: - removes expensive predicate treatment from make_cond_for_table, assuming that the caller should decide whether to evaluate or not expensive predicates, and what to do with them. - saves expensive constant conditions in JOIN::exec_const_cond, which is evaluated once in the beginning of JOIN::exec. " Timour