将两个具有不同模式的 SELECT 语句“生成”的结果连接到一个表中答案

【问题标题】：Join results "generated" from two SELECT statements with different schemas into one table将两个具有不同模式的 SELECT 语句“生成”的结果连接到一个表中
【发布时间】：2011-11-12 17:26:42
【问题描述】：

所以我有以下 SELECT 语句：

SELECT COUNT(A.Award) AS US, SUBSTRING(CAST(M.Year as char(4)), 0 , 4)  AS Decade
FROM Movies M, Awards A
WHERE {SOME WHERE CLAUSE}
GROUP BY Decade;

和

SELECT COUNT(*) AS Total, SUBSTRING(CAST(A2.Year as char(4)), 0 , 4) AS Decade
FROM Awards A2
WHERE {SOME WHERE CLAUSE}
GROUP BY Decade;

第一个是“生成”一个包含列的表 (US, Decade)，第二个是“生成”另一个包含列的表 (Total ，十年）。我想加入这两个表，以便得到一个表（US、Total、Decade）。我该怎么做？

【问题讨论】：

标签： mysql sql postgresql

【解决方案1】：

将它们放在子查询中并执行JOIN：

SELECT a.US, a.decade, b.total FROM

  (SELECT COUNT(A.Award) AS US, SUBSTRING(CAST(M.Year as char(4)), 0 , 4)  AS Decade
  FROM Movies M, Awards A
  WHERE {SOME WHERE CLAUSE}
  GROUP BY Decade ) AS a

INNER JOIN

  (SELECT COUNT(*) AS Total, SUBSTRING(CAST(A2.Year as char(4)), 0 , 4) AS Decade
  FROM Awards A2
  WHERE {SOME WHERE CLAUSE}
  GROUP BY Decade) AS b

ON a.decade = b.decade

【讨论】：