mysql更新带有多个表和左外连接的选择语句

Question

我有两个表，hires_owner 和 projects，其中hires_owner 是项目中数据的汇总表。我想使用项目数据定期更新hires_owner。表结构如下：

**hires_owner**

id INT(11) AUTO-INCREMENT
owner CHAR(25) UNIQUE
hires_total INT(3)

Sample data:
1, tim, 0
2, jack, 3
3, brian, 1
etc.

和

**projects**

id INT(11) AUTO-INCREMENT
date DATE() **this is the report date stamp, not date of activity
owner CHAR(25)
accept DATE()

sample data:
1, 2014-02-01, jack, 2014-01-02
2, 2014-02-01, jack, 2014-01-03
3, 2014-02-01, tim, NULL
etc.

这个查询得到了我想要推送到hires_owner 表中的结果：

select owner, count(accept) 
from projects 
where date = (select max(date) from projects) 
group by owner

...但我似乎无法正确获取更新查询。这是一次尝试：

update hires_owner h
set hires_total = p.Hires   
(select owner, count(accept) as Hires
from projects 
where date = (select max(date) from projects) 
group by owner) p
where p.owner = h.owner

Answer 1

试试这个：-

update
hires_owner h
inner join
(select owner, count(accept) num_c
from projects 
where date = (select max(date) from projects) 
group by owner) p
on h.owner = p.owner
set h.hires_total = num_c

Answer 2

您的查询没有指定要更新的所有者，这有点扭曲逻辑。 更新了，告诉我结果。

update hires_owner set hires_total = p.m
from (select max(count(accept)) as m, owner as o
                   from projects 
                   where date = (select max(date) from projects)
                   group by owner) as p
where hires_owner = p.o;