Mysql SQL是否将一个联接表的多个记录分组?
我有两张MySQL表Mysql SQL是否将一个联接表的多个记录分组?,mysql,sql,grouping,Mysql,Sql,Grouping,我有两张MySQL表 Parent id, name 1, Parent 1 2, Parent 2 Children id, parent_id, name 1,1, Child P1 1 2,1, Child P1 2 3,2, Child P2 1 4,2, Child P2 2 5,2, Child P2 3 我知道从两个表中获取记录的SQL是 Select Parent.id, Parent.name, Children.id, Children.name from Parent
Parent
id, name
1, Parent 1
2, Parent 2
Children
id, parent_id, name
1,1, Child P1 1
2,1, Child P1 2
3,2, Child P2 1
4,2, Child P2 2
5,2, Child P2 3
我知道从两个表中获取记录的SQL是
Select Parent.id, Parent.name, Children.id, Children.name
from Parent
left join Children
on Children.parent_id=Parent.id
这将返回类似于
Parent.id Parent.name Children.id Children.Name
1 Parent 1 1 Child P1 1
1 Parent 1 2 Child P1 2
2 Parent 2 3 Child P2 1
2 Parent 2 4 Child P2 2
2 Parent 2 5 Child P2 3
MySQL中是否有SQL查询可以返回类似的内容
Parent.id Parent.name Children_ids Children_Names
1 Parent 1 1,2 Child P1 1,Child P1 2
2 Parent 2 3,4,5 Child P2 1,Child P2 2,Child P2 3
提前感谢。在MySQL中,您需要使用将多行连接成一行的函数。由于这是一个聚合函数,您还将在查询中使用
GROUP BY
子句:
select p.id,
p.name,
group_concat(c.id order by c.id) ChildrenIds,
group_concat(c.name order by c.id) ChildrenNames
from parent p
left join children c
on p.id = c.parent_id
group by p.id, p.name
看
结果是:
| ID | NAME | CHILDRENIDS | CHILDRENNAMES |
------------------------------------------------------------------
| 1 | Parent 1 | 1,2 | Child P1 1,Child P1 2 |
| 2 | Parent 2 | 3,4,5 | Child P2 1,Child P2 2,Child P2 3 |
使用组_concat
Select Parent.id, Parent.name, group_concat(Children.id) AS 'Children_ids',
group_concat(Children.name) AS 'Children_Names'
from Parent left join Children on Children.parent_id=Parent.id
group by Parent.id, Parent.name;