Question

我目前正在使用此查询..

SELECT sub_id, pm_id, count(*) AS expect FROM `sub_performancemeasures`
WHERE `progress`='0' GROUP BY pm_id

这是查询生成的表..

sub_id | pm_id | expect
     1 | 162   | 4
     1 | 163   | 6
     5 | 164   | 2
     1 | 168   | 5

我还有其他几乎相同的查询...

SELECT sub_id, pm_id, count(*) AS stretch FROM `sub_performancemeasures`
WHERE `progress`='100' GROUP BY pm_id

SELECT sub_id, pm_id, count(*) AS poor FROM `sub_performancemeasures`
WHERE `progress`='-100' GROUP BY pm_id

SELECT sub_id, pm_id, count(*) AS excel FROM `sub_performancemeasures`
WHERE `progress`='200' GROUP BY pm_id

我想要做的是将所有这些合并到一个查询中，结果看起来像这样..

sub_id | pm_id | poor | expect | stretch | excel
     1 |   162 |    4 |      0 |       2 | 5
     1 |   163 |    6 |      9 |       4 | 1 
     5 |   164 |    2 |      1 |       7 | 9
     1 |   168 |    5 |      3 |       5 | 8

Answer 1

您没有加入，而是可以使用conditional sum作为

来加入

select
sub_id, 
pm_id,
sum( case when `progress`='0' then 1 else 0 end ) as expect, 
sum( case when `progress`='100' then 1 else 0 end ) as stretch,
sum( case when `progress`='-100' then 1 else 0 end ) as poor,
sum( case when `progress`='200' then 1 else 0 end ) as excel
from `sub_performancemeasures`
group by pm_id

另请注意，在标准sql中，每个非聚合列都应该在group by子句中，但在mysql中它允许不具有它，但是你应该删除select中不需要的列。

Answer 2

尝试此操作（派生表上的LEFT JOIN）。这适用于期望和伸展，然后您可以轻松扩展为穷人和excel（或将来甚至更多列）：

SELECT sub.sub_id, sub.pm_id, CASE WHEN 
temp_expect.expect IS NOT NULL THEN temp_expect.expect ELSE '0' END AS expect,
CASE WHEN temp_stretch.stretch IS NOT NULL 
THEN temp_stretch.stretch ELSE '0' END AS stretch
FROM sub_performancemeasures sub
LEFT JOIN
(
    SELECT pm_id, count(*) AS expect FROM `sub_performancemeasures`
    WHERE `progress`='0' GROUP BY pm_id
)
AS temp_expect ON sub.pm_id = temp_expect.pm_id
LEFT JOIN
(
    SELECT pm_id, count(*) AS stretch FROM `sub_performancemeasures`
    WHERE `progress`='100' GROUP BY pm_id
)
AS temp_stretch ON sub.pm_id = temp_stretch.pm_id

Answer 3

您可以尝试以下查询： -

{{1}}

Mysql多个查询到一个

3 个答案: