SELECT 与 INNER JOIN 计算增量和过滤结果

Question

我正在尝试 select 表 B 中具有相同id的所有行，并计算表A中的count数值的增量和从 B 中选择的行数，如下所示：

SELECT A.id, 
       A.count, 
       count(*) AS counter, 
       CAST(count(*) AS SIGNED) - CAST(A.count AS SIGNED) AS delta 
FROM table_A AS A 
INNER JOIN table_B AS B ON B.id = A.id 
GROUP BY A.id

现在我计算了delta ，但无法过滤delta > 0的结果我试图在这里和那里放置HAVING delta > 0和WHERE delta > 0 ，但没有运气。 看起来我在我的查询中遗漏了一些带有范围的东西。

Answer 1

尝试使用此查询

SELECT * FROM (SELECT A.id, 
   A.count, 
   count(1) AS counter, 
   CAST(count(1) AS SIGNED) - CAST(A.count AS SIGNED) AS delta 
FROM table_A AS A 
INNER JOIN table_B AS B ON B.id = A.id 
GROUP BY A.id) as t where delta > 0

Answer 2

这是你想要的吗？

SELECT
    a.id, 
    a.count, 
    COUNT(*) AS counter
FROM cdb_A a
INNER JOIN db_B AS B
    ON b.id = a.id
GROUP BY
    a.id
HAVING
    COUNT(*) > a.count;