我似乎经常遇到这个问题,因为我的数据格式如下:
+----+----------------------+ | id | colors | +----+----------------------+ | 1 | Red,Green,Blue | | 2 | Orangered,Periwinkle | +----+----------------------+
但我想要这样格式化:
+----+------------+ | id | colors | +----+------------+ | 1 | Red | | 1 | Green | | 1 | Blue | | 2 | Orangered | | 2 | Periwinkle | +----+------------+
有什么好方法吗?这种操作甚至叫做什么?
我认为这是您需要的(存储过程):Mysql将列字符串拆分为行
DELIMITER $$ DROP PROCEDURE IF EXISTS explode_table $$ CREATE PROCEDURE explode_table(bound VARCHAR(255)) BEGIN DECLARE id INT DEFAULT 0; DECLARE value TEXT; DECLARE occurance INT DEFAULT 0; DECLARE i INT DEFAULT 0; DECLARE splitted_value INT; DECLARE done INT DEFAULT 0; DECLARE cur1 CURSOR FOR SELECT table1.id, table1.value FROM table1 WHERE table1.value != ''; DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = 1; DROP TEMPORARY TABLE IF EXISTS table2; CREATE TEMPORARY TABLE table2( `id` INT NOT NULL, `value` VARCHAR(255) NOT NULL ) ENGINE=Memory; OPEN cur1; read_loop: LOOP FETCH cur1 INTO id, value; IF done THEN LEAVE read_loop; END IF; SET occurance = (SELECT LENGTH(value) - LENGTH(REPLACE(value, bound, '')) +1); SET i=1; WHILE i <= occurance DO SET splitted_value = (SELECT REPLACE(SUBSTRING(SUBSTRING_INDEX(value, bound, i), LENGTH(SUBSTRING_INDEX(value, bound, i - 1)) + 1), ',', '')); INSERT INTO table2 VALUES (id, splitted_value); SET i = i + 1; END WHILE; END LOOP; SELECT * FROM table2; CLOSE cur1; END; $$