有效地合并两个SQL查询

Question

我有两个查询：

1）

SELECT COUNT(*) AS total, COUNT(supporter) AS done FROM Supports;

2）

SELECT supporter, COUNT(supporter) AS amount FROM Supports 
GROUP BY supporter ORDER BY amount DESC LIMIT 1;

如何有效地结合它们？

这是表格的样子：

+-----------------------------+
| id    | name    | supporter |
+-----------------------------+
|    1  | user1   |    sup1   |
|    2  | user1   |    sup2   |
|    3  | user1   |    NULL   |
|    4  | user2   |    sup1   |
|    5  | user2   |    sup3   |
+-----------------------------+

Answer 1

由于需要总数，因此必须使用子查询来合并为一个查询。 将其包括在FROM子句中。

SELECT supporter, COUNT(supporter) AS amount, total, done 
FROM Supports,
    (SELECT COUNT(*) AS total, COUNT(supporter) AS done FROM Supports) totals
GROUP BY supporter
ORDER BY amount DESC
LIMIT 1;

Answer 2

我相信这是您要寻找的：

SELECT
  (SELECT COUNT(*) FROM Supports) as total,
  (SELECT COUNT(supporter) FROM Supports) as done,
  supporter, 
  COUNT(*) AS amount 
FROM Supports 
GROUP BY supporter 
ORDER BY amount;

结果看起来像这样： http : //sqlfiddle.com/#!9/9e4ee/9

total  done  supporter   amount
5      4     sup3        1
5      4     sup2        1
5      4     NULL        1
5      4     sup1        2

Answer 3

SELECT  a.total, a.done, b.supporter, b.amount 
      ( SELECT  COUNT(*) AS total, 
                COUNT(supporter) AS done
            FROM  Supports 
      ) AS a
    JOIN  
      ( SELECT  supporter, 
                COUNT(supporter) AS amount
            FROM  Supports
            GROUP BY  supporter
            ORDER BY  amount DESC
            LIMIT  1 
      ) AS b;