MYSQL第三个内部连接不起作用

Question

我写了一个查询如下，但收到错误

SELECT DISTINCT T2.host, 
 T3.error
FROM table1 T1
INNER JOIN table2 T2
ON
T1.item_id = T2.item_id
INNER JOIN table3 T3
ON
T1.ID = T3.run_id 
and T1.submit_id = (select max(T1.submit_id) from table1 T1) 
;

在这里，T3.run_id = (select max(T3.run_id) from T3)发出错误

我在T3有三排为max(T3.run_id)特定的T1.item_id = T2.item_id

item_id  host
15907    abc.com
7303     cde.com
7304     abcd.com
7305     cdedf.com

以上是table 2 select * from table2 where item_id = '15907';的样本数据

id  submit_id   item_id
49898   16693   15907
49899   16693   15907
49900   16693   15907
53735   17972   15907
53736   17972   15907
53737   17972   15907

以上是table 1 select * from table1 where item_id = '15907';的样本数据

上面我需要用max(submit_id)和T1.item_id = T2.item_id选择行在这个例子中，它将是17972

id  run_id  error
12345   53735   error1
12345   53735   error2
12346   53735   error3
12347   53736   error4
12348   53736   error5
12349   53737   error6

以上是table3 select * from table3 where run_id IN ('53735', '53736', '53737');的样本数据

我得到0行作为输出

Answer 1

您可以如下重写查询以获得预期的输出

SELECT DISTINCT T2.host,T3.error
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 

我在内部查询中移动了table1以获取submit_id最大的id

DEMO

Answer 2

检查下面的输出

SELECT DISTINCT T2.host 
     ,T3.error
    FROM table1 T1
    INNER JOIN table2  T2 ON T1.item_id = T2.item_id
    and T1.submit_id = (select max(T1.submit_id) from table1  T1 )
    INNER JOIN table3 T3 ON T1.ID = T3.run_id 
    ;

产量

host    error
abc.com error1
abc.com error2
abc.com error3
abc.com error4
abc.com error5
abc.com error6