MySQL:计算分组项目吗? [英] MySQL: count grouped items?

问题描述

基本上，可以说我的数据库表有两列:关键字和日期.

Basically, ok say my DB table has 2 columns: keyword and date.

我想选择行，但是如果多行具有相同的关键字和日期，我想将它们分组并计算出有多少行.

I want to select rows but if multiple rows have the same keyword and date I want to group them and get a count of how many there are.

例如，而不是得到这个:

for example instead of getting this:

keyword: diamond, date: 20090601
keyword: diamond, date: 20090601
keyword: diamond, date: 20090602
keyword: diamond, date: 20090602
keyword: diamond, date: 20090602

我会得到这个:

keyword: diamond, date: 20090601, count: 2
keyword: diamond, date: 20090602, count: 3

不确定如何做到吗?

谢谢！

推荐答案

它称为 GROUP BY 子句:

It's called the GROUP BY clause:

SELECT keyword, date, COUNT(1) AS count
FROM table
GROUP BY keyword, date

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