Question

我在数据库中有一个非常简单的表，其中有3列名为people。例如：

user           id             notes
john           01             has red hair, last logged in 02/04/12
tony           02             has brown hair, last logged in 04/03/12
brian          03             has brown hair, last logged in 03/06/13
amanda         04             has blonde hair, last logged in 05/07/14
…

如果我想按注释字段分组并进行计数，则第2行和第3行显示为1的计数，因为登录日期不同;我想做的是砍掉日期并合并并完全按头发颜色计算，例如如果我运行查询：

SELECT `notes`, COUNT( `user` ) AS Count 
FROM `people` 
WHERE `notes` LIKE "%hair%" GROUP BY `notes`;

我得到的结果是：

+-----------------------------------------+-------+
|notes                                    | Count |
+-----------------------------------------+-------+
|has red hair, last logged in 02/04/12    |      1|
|has brown hair, last logged in 04/03/12  |      1|
|has brown hair, last logged in 03/06/13  |      1|
|has blonde hair, last logged in 05/07/14 |      1|
+-----------------------------------------+-------+

希望实现以下结果：

+-------------------+------+
|notes              |Count | 
+-------------------+------+
|has red hair       |     1|
|has brown hair     |     2|
|has blonde hair    |     1|
+-------------------+------+

这一切都可能吗？

干杯。

Answer 1

您可以使用SUBSTRING_INDEX执行此操作，如下所示：

SELECT SUBSTRING_INDEX(`notes`, ',', 1), COUNT( `user` ) AS Count
FROM `people`
WHERE `notes` LIKE "%hair%"
GROUP BY SUBSTRING_INDEX(`notes`, ',', 1)

当然这是一个有点脏的解决方法。更好的方法是分离头发颜色，但我意识到这可能并不总是可能。

Demo

返回SQL LIKE＆amp; GROUP BY结果

1 个答案: