Question

我有下表

表：时间

timeid   time
1        10    
2        11   
3        3

表：计数

countId timeID numberCounts times
1       1      1            0
2       2      3            11
2       2      3            12
3       2      3            13
4       3      1            0

查询我正在使用

SELECT

t.time AS "Start Channel",
c.times AS Lapse

FROM Times t

JOIN Count c ON c.Time_ID=t.Time_ID;

输出

+---------------+----------+
| Start Time    | lapse    |
+---------------+----------+
|          10   |        0 | 
|          11   |       11 | 
|          11   |       12 | 
|          11   |       13 | 
|           3   |        0 | 
+---------------+----------+

欲望结果：

+---------------+
|     TimeS     |
+---------------+
|          10   | 
|          11   | 
|          12   | 
|          13   | 
|           3   | 
+---------------+

Answer 1

根据您想要的结果，您似乎想要：

SELECT GREATEST(t.time, c.times) AS `TimeS`
  FROM Times AS t
  JOIN Count AS c
    ON c.Time_ID = t.Time_ID
;

但你问题的标题听起来像你想要的那样：

SELECT time AS `TimeS`
  FROM Times
UNION
SELECT times
  FROM Count
;

（在结果中也会包含0，因为Count.times有时是0）。

Answer 2

您需要学习DISTINCT关键字，简单快捷的解决方案：）

MySQL如何将两列合并为一列，只显示不同的值？

2 个答案: