Question

我如何能够加入下面的2个表格（A＆amp; B），以便我可以得到下面的结果表

请注意，查询应该加入具有相同时间的值，

（即结果表中显示如下2014-11-29 9:58:23 6054 1）

表A

ID      time                noise
76676   2014-11-29 09:55:24 6636
76677   2014-11-29 09:55:32 5256
76678   2014-11-29 09:55:42 5066
76679   2014-11-29 09:56:09 11560
76680   2014-11-29 09:56:22 5656
76681   2014-11-29 09:56:50 7031
76682   2014-11-29 09:56:56 5069
76683   2014-11-29 09:57:06 10088
76684   2014-11-29 09:57:23 5589
76685   2014-11-29 09:58:23 6054

表B

ID  time                movement
789 2014-11-29 09:57:04 1
790 2014-11-29 09:57:10 1
791 2014-11-29 09:57:30 1
792 2014-11-29 09:57:34 1
793 2014-11-29 09:57:40 1
794 2014-11-29 09:57:43 1
795 2014-11-29 09:57:52 1
796 2014-11-29 09:58:09 1
797 2014-11-29 09:58:23 1
798 2014-11-29 09:58:31 1

结果：

time                noise   movement
2014-11-29 9:55:24  6636    null
2014-11-29 9:55:32  5256    null
2014-11-29 9:55:42  5066    null
2014-11-29 9:56:09  11560   null
2014-11-29 9:56:22  5656    null
2014-11-29 9:56:50  7031    null
2014-11-29 9:56:56  5069    null
2014-11-29 9:57:04  null    1
2014-11-29 9:57:06  10088   null
2014-11-29 9:57:10  null    1
2014-11-29 9:57:23  5589    null
2014-11-29 9:57:30  null    1
2014-11-29 9:57:34  null    1
2014-11-29 9:57:40  null    1
2014-11-29 9:57:43  null    1
2014-11-29 9:57:52  null    1
2014-11-29 9:58:09  null    1
2014-11-29 9:58:23  6054    1
2014-11-29 9:58:31  null    1

Answer 1

您需要执行Jynus已经评论过的FULL OUTER JOIN。

select t1.time,t1.noise,t2.movement 
from TableA t1 left join TableB t2
on t1.time = t2.time
UNION
select t1.time,t1.noise,t2.movement 
from TableA t1 right join TableB t2
on t1.time = t2.time;

根据您的上一条评论：这是正确的，因为该行来自RIGHT JOIN，但您可以使用CASE表达式稍微调整一下

case when t1.time is null then t2.time else t1.time end as time

或者只是在t2.time查询中使用RIGHT JOIN，如@Karlois指出

在此处查看演示http://sqlfiddle.com/#!2/d42d01/2

SELECT * FROM
(
select t1.time,t1.noise,t2.movement 
from TableA t1 left join TableB t2
on t1.time = t2.time
UNION
select t2.time,
t1.noise,t2.movement 
from TableA t1 right join TableB t2
on t1.time = t2.time
) tab
ORDER BY time;

Answer 2

首先你需要将两个表的时间联合起来，然后用两个表创建连接以获得噪声和运动

SELECT ts.time, ta.noise, tb.movement 
  FROM (SELECT a.time from tablea a
        UNION
        SELECT b.time from tableb b) ts 
    LEFT OUTER JOIN tablea ta ON ts.time = ta.time
    LEFT OUTER JOIN tableb tb ON ts.time = tb.time

Answer 3

我喜欢union和聚合完全外连接的方法：

select time, max(noise) as noise, max(movement) as movement
from ((select a.time, a.noise, NULL as movement
       from tablea a
      ) union all
      (select b.time, NULL, b.movement
       from tableb b
      )
     ) ab
group by time;

完全连接2个表与共同时间

3 个答案: