how save a selected record into a variable? - mysql

Question

I'm in a problem with the following query ..
After inserting in the table rtoxvta record by record, I need before the end of the loop eliminate the record of the vta table prevously selected.
For that i declare a new variable and assign it the vta id .. but where do I do it?
DROP PROCEDURE IF EXISTS ROWPERROW;
DELIMITER ;;
CREATE PROCEDURE ROWPERROW()
BEGIN
DECLARE n INT DEFAULT 0;
DECLARE indexx INT DEFAULT 0;
#DECLARE aux INT DEFAULT 0;
SELECT COUNT(*) FROM rto INTO n;
SET n = n +1;
SET indexx=0;
WHILE indexx<n DO
INSERT INTO rtoxvta (fecharto, importerto, fechavta, importevta)
SELECT r.fecha, r.importe, v.fecha, v.importe
FROM vta v
left outer join rto r
ON r.id = indexx
WHERE v.fecha >= r.fecha
AND (
(v.importe = r.importe) OR
(v.importe + 2 = r.importe) OR
(v.importe + 1 = r.importe) OR
(v.importe - 1 = r.importe) OR
(v.importe - 2 = r.importe))
LIMIT 1;
SET indexx = indexx + 1;
#DELETE FROM vta WHERE id = aux;
END WHILE;
End;
;;
CALL ROWPERROW();

Answer 1

You'll have to do it as two steps. First get the ID of the record you're going to insert into a variable, then insert that record. Then you can delete the record.
WHILE indexx<n DO
SELECT v.id, r.id INTO #v_id, #r_id
FROM vta v
join rto r
ON r.id = indexx
WHERE v.fecha >= r.fecha
AND r.importe BETWEEN v.importe - 2 AND v.importe + 2
LIMIT 1;
INSERT INTO rtoxvta (fecharto, importerto, fechavta, importevta)
SELECT r.fecha, r.importe, v.fecha, v.importe
FROM vta v
CROSS JOIN rto r
WHERE v.id = #v_id AND r.id = #r_id;
SET indexx = indexx + 1;
DELETE FROM vta WHERE id = #v_id;
END WHILE;
Also, if you're using a column from rto in the WHERE clause, you should use INNER JOIN rather than LEFT OUTER JOIN. The WHERE condition will not match any rows that don't have a match in rto, so there's no point in using an outer join.