SQL Count() 列值 [英] SQL Count() column values

问题描述

我有以下源表:

pid | code
----------
1      P2
2      P2
3      P3
4      P1
5      P2
6      P1

现在，我想获取每个代码存在多少次的信息:

Now, I want to get the information how many times each code exists:

code | count
------------
P2      3
P1      2
P3      1

所以我想计算代码列中的值并将其分配给一组不同的可用代码值.最后我想按计数订购.

So I want to count the values from code column and assign it to the distinct set of available code values. Finally I want to order by count number.

推荐答案

SQL小提琴:

SELECT t.code, COUNT(*) AS `count`
FROM MyTable t
GROUP BY t.code
ORDER BY COUNT(*) DESC

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