Question

我这里的情况很“简单”，但我自己无法解决。因此，我需要将第一个查询的结果与第二个查询的结果相结合，以获得“最终结果”。

第一个查询获取按玩家拍摄的张数。

SELECT player, COUNT(shot) shots FROM table1 GROUP BY player;

+---------+-------+
| player  | shots |
+---------+-------+
| player1 | 10    |
+---------+-------+
| player2 | 10    |
+---------+-------+

第二个是获得点击。

SELECT player, COUNT(hit) hits FROM table2 GROUP BY player;

+---------+-------+
| player  | hits  |
+---------+-------+
| player1 | 10    |
+---------+-------+
| player2 | 5     |
+---------+-------+

我需要计算准确度（命中/击球* 100），并显示类似结果。

+---------+-------+------+-----+
| player  | shots | hits | acc |
+---------+-------+------+-----+
| player1 | 10    | 10   | 100 |
+---------+-------+------+-----+
| player2 | 10    | 5    | 50  |
+---------+-------+------+-----+

Answer 1

您可以在汇总后使用join：

SELECT player, s.shots, h.hits
FROM (SELECT player, COUNT(shot) as shots
      FROM table1
      GROUP BY player
     ) s JOIN
     (SELECT player, COUNT(hit) as hits
      FROM table2
      GROUP BY player
     ) h
     USING (player);

您真的打算COUNT()吗？看来SUM()会更合适。

此外，这只会返回两个表中的玩家。如果您想让任一表中的玩家，请使用FULL JOIN。

PostgreSQL |合并查询结果

1 个答案: