Question

假设我的数据库中有2个表，

第一个：

TABLE "SONGS"
+----+-------+--------+
| id | title | artist |
+----+-------+--------+
|  1 | song1 |   blah |
|  2 | song2 |   wut? |
|  3 | song3 | random |
+----+-------+--------+

还有一个：

TABLE "PLAYS"
+----+---------+--------+
| id | song_id |  time  |
+----+---------+--------+
|  1 |       2 |  13:04 |
|  2 |       1 |  13:07 |
|  3 |       1 |  14:30 |
|  4 |       3 |  14:41 |
|  5 |       2 |  14:59 |
|  6 |       1 |  15:32 |
+----+---------+--------+

我试图让我的脚本从表song_id中查询最常见的plays，然后将其与title中的artist和songs一起加入}表格为广播电台制作音乐图表，但到目前为止还没有运气得到结果。

这是预期的结果：

[
    {"song_id": 1, "title": "song1", "artist": "blah", "plays": 3},
    {"song_id": 2, "title": "song2", "artist": "wut?", "plays": 2},
    {"song_id": 3, "title": "song3", "artist": "random", "plays": 1}
]

提前谢谢。

Answer 1

你可以在表之间进行常规的JOIN，计算每个id / artist / title的行数和按顺序排序;

SELECT s.id, s.title, s.artist, COUNT(*) plays
FROM songs s
JOIN plays p
  On s.id = p.song_id
GROUP BY s.id, s.title, s.artist
ORDER BY plays DESC

An SQLfiddle to test with

只需一个id就可以获得播放顺序，无需加入;

SELECT song_id, COUNT(*) plays
FROM plays p
GROUP BY song_id
ORDER BY plays DESC

Another SQLfiddle

要获得前5个结果，可以将LIMIT 5添加到任一查询中。

选择前5个最常见的行并从另一个表中查询数据

1 个答案: