Mysql 仅返回多个重复父id的Child表上最后插入的父id
我正在尝试获取childs表上最后插入的父id的值,然后加入 祖父母表以获取财产及其总数 以下是我的表格结构:Mysql 仅返回多个重复父id的Child表上最后插入的父id,mysql,sql,greatest-n-per-group,Mysql,Sql,Greatest N Per Group,我正在尝试获取childs表上最后插入的父id的值,然后加入 祖父母表以获取财产及其总数 以下是我的表格结构: parents +------------ |pid | item | +----+------+ | 1 | ite1 | | 2 | ite2 | +-----------+ childs +-------------+ | cid | pid | +------+------+ | 1 | 1 | -- not | 2 | 1 | ---- ro
parents
+------------
|pid | item |
+----+------+
| 1 | ite1 |
| 2 | ite2 |
+-----------+
childs
+-------------+
| cid | pid |
+------+------+
| 1 | 1 | -- not
| 2 | 1 | ---- row to be selected(last inserted to join grandparents)
| 3 | 2 | -- not
| 4 | 2 | ---- row to be selected(last inserted to join grandparents)
+-------------+
grandparents
+----------------------+
| gid | cid | property |
+-----+-----+----------+
| 1 | 1 | 1200 |
| 2 | 1 | 1500 |
| 3 | 2 | 101 |
| 4 | 2 | 303 |
| 5 | 3 | 600 |
| 6 | 3 | 10 |
| 7 | 4 | 335 |
| 8 | 4 | 250 |
+----------------------+
结果
+----------------------------+
| item | cid | property |
+--------+------+------------+
| ite1 | 2 | 101 |
| ite1 | 2 | 303 |
| ite1 | 4 | 335 |
| ite1 | 4 | 250 |
+----------------------------+
Total property results : sum(101 + 303 +335 + 250) = 989
我尝试了这个查询,但返回/包括导致
整个祖父母表的总数
query:
SELECT g.property from grandparents g
join childs c on g.cid = c.cid
join parents p on c.pid = p.pid
where c.pid in (select DISTINCT pid from childs) and c.pid = 1
您可以尝试使用子查询获取
MAX(cid)
,然后通过子查询的cid
JOIN
SELECT g.property
from grandparents g
join (
SELECT pid ,MAX(cid) cid
FROM childs
GROUP BY pid
) c on g.cid = c.cid
join parents p on c.pid = p.pid
您可以尝试使用子查询获取
MAX(cid)
,然后通过子查询的cid
JOIN
SELECT g.property
from grandparents g
join (
SELECT pid ,MAX(cid) cid
FROM childs
GROUP BY pid
) c on g.cid = c.cid
join parents p on c.pid = p.pid
您的mysql版本是什么?您好,我正在使用mysqlnd 7.4.5您的mysql版本是什么?您好,我正在使用mysqlnd 7.4.5非常感谢!这个解决方案很好@D-shih非常感谢!此解决方案在D-Shih中效果良好