mysql - 从一列中选择重复值并在一行中获取该值

Question

我有一个包含 2 列的表格，如下所示

+----------+----------+
| Column A | Column B |
+----------+----------+
|      123 |    ABC   |
|      123 |    XYC   |
|      123 |    FGH   |
|      145 |    QWE   |
|      147 |    YUI   |
+----------+----------+

我想从表中选择所有值，但查看如下:

+----------+---------+---------+----------+
| Column A | value 1 | value 2 | value 3  |
+----------+---------+---------+----------+
|      123 | ABC     | XYC     | FGH      |
|      145 | QWE     |         |          |
|      147 | YUI     |         |          |
+----------+---------+---------+----------+

Answer 1

如果您不想在输出中创建额外的列，则可以简单地使用 GROUP_CONCAT与您选择的分隔符。例如:

SELECT `Column A`, 
       GROUP_CONCAT(`Column B` SEPARATOR ' | ') AS `Values`
FROM table1
GROUP BY `Column A`

输出:

Column A    Values
123         ABC | XYC | FGH
145         QWE
147         YUI

Demo on dbfiddle