Is there something like a FOR loop in MySql? - mysql

Question

I have a table with matches information, and I need to return a row for each goal and each team. So for example:
+--------+-------+-------+-------+-------+
| Match | Team1 | goal1 | goal2 | Team2 |
+--------+-------+-------+-------+-------+
| 1 | Red | 1 | 0 | Blue |
+--------+-------+-------+-------+-------+
| 2 | Green | 2 | 1 | Black |
+--------+-------+-------+-------+-------+
I want to run a function for each row that returns a row for each goal for each team. So my function result would be:
+--------+-------+-------+
| Goal | Match | Team |
+--------+-------+-------+
| 1 | 1 | Red |
+--------+-------+-------+
| 2 | 2 | Green |
+--------+-------+-------+
| 3 | 2 | Green |
+--------+-------+-------+
| 4 | 2 | Black |
+--------+-------+-------+
My ultimate objective is that I need to have one row for each match/team/goal to fill in manually the Scorer and the minute. Since I hace over 40000 matches, copy pasting each row counting the amount of goals is a pain.
I would like to start with a goal table pre populated with as much information as I already have.

Answer 1

Create a table that contains numbers from 1 to the maximum number of possible goals, i.e.
CREATE TABLE numbers (
num INT PRIMARY KEY
);
INSERT INTO numbers VALUES (1), (2), (3), (4), (5), (6), ...
You can then join this table with your original table:
SELECT num AS Goal, `Match`, Team
FROM numbers
JOIN (
SELECT Team1 AS Team, goal1 AS goals, `Match`
FROM matches
UNION
SELECT Team2 AS Team, goal2 AS goals, `Match`
FROM matches
) ON num <= goals

Answer 2

While loop syntax example in MySQL:
delimiter //
CREATE procedure yourdatabase.while_example()
wholeblock:BEGIN
declare str VARCHAR(255) default '';
declare x INT default 0;
SET x = 1;
WHILE x <= 5 DO
SET str = CONCAT(str,x,',');
SET x = x + 1;
END WHILE;
select str;
END//
Which prints:
mysql> call while_example();
+------------+
| str |
+------------+
| 1,2,3,4,5, |
+------------+
FOR loop syntax example in MySQL:
delimiter //
CREATE procedure yourdatabase.for_loop_example()
wholeblock:BEGIN
DECLARE x INT;
DECLARE str VARCHAR(255);
SET x = -5;
SET str = '';
loop_label: LOOP
IF x > 0 THEN
LEAVE loop_label;
END IF;
SET str = CONCAT(str,x,',');
SET x = x + 1;
ITERATE loop_label;
END LOOP;
SELECT str;
END//
Which prints:
mysql> call for_loop_example();
+-------------------+
| str |
+-------------------+
| -5,-4,-3,-2,-1,0, |
+-------------------+
1 row in set (0.00 sec)
Tutorial: http://www.mysqltutorial.org/stored-procedures-loop.aspx