使用mysql在一个查询中选择多个表中的子项总数

我整个下午都在尝试处理查询(或两个或三个)以获得三个表的所有孩子的计数.看看我的设计：

用户表

id_user | name
1 | foo
2 | bar

wons表

id_won | user
1 | 1
2 | 1
3 | 2

绘制表格

id_draw | user
1 | 1
2 | 2
3 | 2

失去了桌子

id_lose | user
1 | 1
2 | 1
3 | 1

我想要得到这样的东西：

name | wons | draws | loses
foo | 2 | 1 | 3
bar | 1 | 2 | 0

这是我的尝试：

select 
    u.name, w.total_w, d.total_d, l.total_l
from 
    user u
    LEFT JOIN 
    (select count(user) as total_w, user from wons group by user) as w
    ON w.user = u.id_user
    LEFT JOIN 
    (select count(user) as total_d, user from draws group by user) as d 
    ON d.user = w.user
    LEFT JOIN 
    (select count(user) as total_l, user from loses group by user) as l 
    ON d.user= .user

group by u.id_user;

解决方法:

select u.name, w.uw as wins, l.ul as loses, d.ud as draws from user
    left join (select user, COUNT(id_won) uw from wons group by user) w on w.user = u.user_id
    left join (select user, COUNT(id_lose) ul from loses group by user) l on l.user = u.user_id
    left join (select user, COUNT(id_draw) ud from draws group by user) d on d.user = u.user_id

这个只需要完成任务所需的工作量.

标签：multiple-tables,sql,mysql,count
来源： https://codeday.me/bug/20190729/1571085.html