Question

我目前有一张包含专辑名称，艺术家和标题的表格（适用于Mp3s）。在我左侧的网页上，我目前使用以下方式显示所有相册名称：

SELEC DISTINCT `album` FROM `mp3`

但我想在旁边显示每张专辑的数量，例如：

A Very Good Album (3)

表示该记录中有3个entires。我可以用SQL做到这一点吗？选择Distinct，还要查看该专辑的数量是多少？

Answer 1

而不是DISTINCT，这实际上是由album分组的基本COUNT() aggregate。

SELECT
  album,
  COUNT(*) AS num_records
FROM 
  mp3
GROUP BY album

如果您想在SQL查询中的括号中使用它，请使用CONCAT()。这可能最好留给您的应用程序进行显示。

SELECT /* The album title, and count in () as one column as a single string */ /* like "A Very Good Album (3)" */ CONCAT(album, ' (', COUNT(*), ')') AS album FROM mp3 GROUP BY album

Answer 2

试试这个：

SELECT `album`, COUNT(*) FROM `mp3` GROUP BY `album`

Answer 3

您需要group by：

select album, count(*)
from mp3
group by album

Answer 4

使用group by并连接像这样的字符串

SELECT
    CONCAT(`album`, ' (', COUNT(*), ')') as album
FROM `mp3`
GROUP BY `album`

Answer 5

查看Count()和Group By

Answer 6

SELECT DISTINCT CONCAT(album, ' (', COUNT(DISTINCT album), ')') AS album
FROM            mp3
GROUP BY        album

SQL DISTINCT加计数

6 个答案: