返回SQL LIKE＆GROUP BY結果

Question

我在數據庫中有一個非常簡單的表，其中包含3列名為people列。 例：

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
…

如果我想按注釋字段分組並進行計數，則第2行和第3行顯示為1，因為登錄日期不同; 我想做的是砍掉日期和合並並純粹按頭發顏色計算，例如，如果我運行查詢：

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

我得到的結果是：

+-----------------------------------------+-------+
|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|
+-----------------------------------------+-------+

想要達到以下結果：

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

這是可能嗎？

干杯。

Answer 1

您可以使用SUBSTRING_INDEX來執行此操作，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)

當然這是一個有點骯臟的解決方法。 更好的方法是分離頭發顏色，但我意識到這可能並不總是可行的。

演示