MySql 将多行中的值选择到一行中

Question

我有一个包含 4 行的表，其中保存了日期时间值。

查询:

SELECT row1, row2, row3, row4 FROM table;

显示此结果:

+------------+------------+------------+------------+
|    row1    |    row2    |    row3    |    row4    |
+------------+------------+------------+------------+
|01.01.2014  |null        |null        |31.12.2018  |
|null        |17.08.2015  |01.12.2050  |null        |
|02.01.2010  |null        |28.03.2067  |null        |
+------------+------------+------------+------------+

但我想将这些日期组合并排序为一行，例如:

+------------+
|    rows    |
+------------+
|01.01.2014  |
|02.01.2010  |
|17.08.2015  |
|01.12.2050  |
|28.03.2067  |
|31.12.2018  |
+------------+

我必须使用什么查询才能获得我想要的结果？

提前致谢

Answer 1

SELECT row1 AS rows FROM table WHERE row1 IS NOT NULL
UNION ALL
SELECT row2 AS rows FROM table WHERE row2 IS NOT NULL
UNION ALL
SELECT row3 AS rows FROM table WHERE row3 IS NOT NULL
UNION ALL
SELECT row4 AS rows FROM table WHERE row4 IS NOT NULL
ORDER BY rows DESC;

我猜会做你想做的事。

您是否有有关该问题的更多信息，例如表和列名称。