IN IN JOIN如何？

Question

使用JOIN ..how写下这个？ 因为这是很慢..

SELECT * 
FROM table1 
WHERE ID IN (SELECT ID 
      FROM table1 
      GROUP BY ID 
      HAVING COUNT(*) = 2 
      AND MAX(awaiting) = 1) 
AND awaiting = 1 

所以，我该怎么写？

Answer 1

SELECT t1.* 
FROM table1 AS t1 
INNER JOIN 
(
    SELECT ID 
    FROM table1 
    GROUP BY ID 
    HAVING COUNT(*) = 2 
     AND MAX(awaiting) = 1 
) AS t2 ON t1.ID = t1.ID AND t1.awaiting = t2.awaiting 
WHERE t1.awaiting = 1; 

Answer 2

这里是join版本：

SELECT t1.* 
FROM table1 t1 join 
    (SELECT ID 
     FROM table1 
     GROUP BY ID 
     HAVING COUNT(*) = 2 AND MAX(awaiting) = 1 
    ) tsum 
    on t1.id = tsum.id 
WHERE t1.awaiting = 1 

Answer 3

我猜awaiting为0或1。如果是在你的内部查询MAX(awaiting) = 1是因为多余的WHERE语句awaiting = 1

此外，在这种情况下，您可以使用以下查询。

SELECT * 
FROM table1 as T1 
WHERE 
awaiting = 1 
AND 
(SELECT count(*) FROM table1 WHERE ID=T1.ID)=2