I have two tables. Both contains question id field. I want to get all records from first table that are not present in second one. I don't want to use "NOT IN" constrain as second table having more than 400000 records.
Try something like
SELECt t1.* FROM Table1 t1 LEFT JOIN Table2 t2 ON t1.questionID = t2.questionID WHERE t2.questionID IS NULL