列转多行---Mysql

Posted 2021-06-22 jiujiujiujiujiujiu

数据准备：

CREATE TABLE   test   (  num varchar(100), score varchar(100)   );

INSERT INTO test(num, score)  VALUES(\'1\', \'2,5,4\');
INSERT INTO test(num, score)  VALUES(\'2\', \'4\');
INSERT INTO test(num, score)  VALUES(\'3\', \'2,5,5,3,4\');

原始：

 

 

列转多行：

select SUBSTRING_INDEX(SUBSTRING_INDEX(score , \',\' , b.help_topic_id+1 ) , \',\' , -1)
from test  a
join mysql.help_topic b
on b.help_topic_id<LENGTH(a.score)-LENGTH(REPLACE(a.score, \',\' ,\'\'))+1

 结果：