How to check the existence of two columns' data in two different tables ? MySQL

Question

I have two different tables in two different databases ..

what I want to do is to check if the data of two columns exist in the other table .. if it does exist count

Answer 1

Do an INNER JOIN on both tables:

SELECT COUNT(*)
FROM table_1 t1
INNER JOIN table_2 t2
    ON t1.column_1 = t2.column_1
    AND t1.column_2 = t2.column_2