sql -删除具有两个相同列值的行。
sql -删除具有两个相同列值的行。
提问于 2017-04-22 23:17:47
表1
|-------------------------------|
| empid | scheddate| schedule|
|-------------------------------|
| 1 |2017-04-21 | null |
|-------------------------------|
| 1 |2017-04-22 | null |
|-------------------------------|
| 1 |2017-04-23 | null |
|-------------------------------|
| 1 |2017-04-24 | null |
|-------------------------------|
| 1 |2017-04-25 | null |
|-------------------------------|
| 1 |2017-04-26 | null |
|-------------------------------|table2
|-------------------------------|
| empid | scheddate| schedule|
|-------------------------------|
| 1 |2017-04-21 | 8-5 |
|-------------------------------|
| 1 |2017-04-22 | 8-5 |
|-------------------------------|
| 1 |2017-04-23 | 8-5 |
|-------------------------------|
| 2 |2017-04-21 | 8-5 |
|-------------------------------|
| 2 |2017-04-22 | 8-5 |
|-------------------------------|
| 2 |2017-04-23 | 8-5 |
|-------------------------------|使用
insert into table3
select * from table1 union select * from table2我有
表3
|-------------------------------|
| empid | scheddate| schedule|
|-------------------------------|
| 1 |2017-04-21 | null |
|-------------------------------|
| 1 |2017-04-22 | null |
|-------------------------------|
| 1 |2017-04-23 | null |
|-------------------------------|
| 1 |2017-04-24 | null |
|-------------------------------|
| 1 |2017-04-25 | null |
|-------------------------------|
| 1 |2017-04-26 | null |
|-------------------------------|
| 1 |2017-04-21 | 8-5 |
|-------------------------------|
| 1 |2017-04-22 | 8-5 |
|-------------------------------|
| 1 |2017-04-23 | 8-5 |
|-------------------------------|
| 2 |2017-04-21 | 8-5 |
|-------------------------------|
| 2 |2017-04-22 | 8-5 |
|-------------------------------|
| 2 |2017-04-23 | 8-5 |
|-------------------------------|我想知道如何得到这样的结果
|-------------------------------|
| empid | scheddate| schedule|
|-------------------------------|
| 1 |2017-04-24 | null |
|-------------------------------|
| 1 |2017-04-25 | null |
|-------------------------------|
| 1 |2017-04-26 | null |
|-------------------------------|
| 1 |2017-04-21 | 8-5 |
|-------------------------------|
| 1 |2017-04-22 | 8-5 |
|-------------------------------|
| 1 |2017-04-23 | 8-5 |
|-------------------------------|
| 2 |2017-04-21 | 8-5 |
|-------------------------------|
| 2 |2017-04-22 | 8-5 |
|-------------------------------|
| 2 |2017-04-23 | 8-5 |
|-------------------------------|回答 1
Stack Overflow用户
回答已采纳
发布于 2017-04-22 23:22:22
你似乎想要这种逻辑：
insert into table3 (empid, scheddate, schedule) -- should always list columns
select empid, scheddate, schedule
from table1 t1
where not exists (select 1 from table2 t2 where t2.empid = t1.empid and t2.scheddate = t1.scheddate)
union all
select empid, scheddate, schedule
from table2;页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/43565651
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