Select data from two tables with loop in mysql

Question

I want to create a loop in mysql.

I have 2 tables, and I want to select all data from table A and result from table A for get data in table B.

For example CASE:

SELECT * FROM table_A;

Result:

Column_1  Column 2
-------------------
A         B
A1        B1
ABC       CDS

Query:

SELECT * 
FROM table_B 
WHERE column = (...result from table_A....)

I want show all data using loop in mysql

CREATE PROCEDURE ROWPERROW()
BEGIN
DECLARE n INT DEFAULT 0;
DECLARE i INT DEFAULT 0;
SELECT * FROM table_A ;
SET i=0;
WHILE i<n DO 

............TABLE_B

END WHILE;
END;
;;

Answer 1

you could use an INNER JOIN for obtain the result wit a single query

SELECT b.* 
FROM table_B b
INNER JOIN  table_A a ON a.column_1 = b.col1 and a.column_2 = b.col2