最佳答案
SELECT
DISTINCT
foo2.group_id AS group_id,
if(foo1.group_id = foo2.group_id, foo1.id, NULL) AS id,
if(foo1.group_id = foo2.group_id, foo1.some_attr, NULL) AS some_attr
FROM mytable AS foo1
JOIN
(SELECT DISTINCT group_id FROM mytable) as foo2
ORDER BY group_id, id
关于MySQL如何分组为行的子组,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43286667/