Question

我编写了一个包含3个连接和3个表的查询，如下所示：

SELECT 
T3.fault, count(*)
FROM table2 T2 
INNER JOIN (
    SELECT a.*
    FROM table1 a
    LEFT JOIN table1 b ON a.item_id = b.item_id AND a.submit_id < b.submit_id
    WHERE b.submit_id IS NULL
) T1  ON T1.item_id = T2.item_id
INNER JOIN table3 T3 ON T1.id = T3.run_id
group by T3.fault
order by count(*) desc;

我的table3如下所示：

id      run_id  runname_id  status  fault
134049  16736   312         FAIL    error1
134050  16736   313         FAIL    error2
134051  16736   314         FAIL    error3
134052  16736   315         PASS    error4
134053  16736   316         PASS    error5

我有一个静态表table4，如下所示：

id  name
312 name1
313 name2
314 name3
315 name4
316 name5

我想在查询中加入table4，以便我的输出也应包含name中的table4。每个error在name中都有相应的table4我想要包含该名称

fault   count(*) name
error1  6        name1

Answer 1

只有LEFT JOIN table4和T4.name列到所选列列表。

SELECT 
T3.fault, count(*), t4.name
FROM table2 T2 
INNER JOIN (
    SELECT a.*
    FROM table1 a
    LEFT JOIN table1 b ON a.item_id = b.item_id AND a.submit_id < b.submit_id
    WHERE b.submit_id IS NULL
) T1  ON T1.item_id = T2.item_id
INNER JOIN table3 T3 ON T1.id = T3.run_id
LEFT JOIN table4 T4
ON 3.runname_id  = T4.id
group by T3.fault
order by count(*) desc;

Answer 2

我会做这样的事情。

SELECT A.fault, A.count, T4.name FROM TABLE4 T4 JOIN(
SELECT 
T3.fault as fault, count(*) as count, T3.run_id as run_id
FROM table2 T2 
INNER JOIN (
    SELECT a.*
    FROM table1 a
    LEFT JOIN table1 b ON a.item_id = b.item_id AND a.submit_id < b.submit_id
    WHERE b.submit_id IS NULL
) T1  ON T1.item_id = T2.item_id
INNER JOIN table3 T3 ON T1.id = T3.run_id
group by T3.fault) A ON A.run_id = T4.id
order by A.count desc;

没有测试过，但据我所知，它只是将第4个表与子查询表合并。因此，您的查询将返回带有fault，count和id的结果。然后我们将此表与id上的表4合并，并按desc对计数进行排序。如果我对这个问题有错误的理解，请纠正我

在mysql join中添加第四个表

2 个答案: