用于从两个表中选择数据的单行查询 [英] single line query for selecting data from two tables

问题描述

大家好，



我有两张桌子t1和t2

Hello everyone,

I have two tables t1 and t2

table t1--

id     name
1       a
2       b
3       c
4       d
5       e

table t2 --

id     name
2       c
3       r
5       z

i want output using a single line query as :

id    name
1      a
2      c
3      r
4      d
5      z

< br $>










即时id列在表t1和t2中匹配然后它应该从表t2中选择名称，否则从表t1中选择



i使用临时表完成此操作..但我希望它在一行查询



请帮帮我..



谢谢&问候

krunal panchal

that is when the id column matches in table t1 and t2 then it should select name from table t2 else from table t1

i have done this using temporary tables..but i want it in a single line query

please help me out..

thanks & regards
krunal panchal

推荐答案

这样......

this way...

select t1.id,case when t2.name is null then t1.name else t2.name end as name
from t1
left join t2 on t1.id=t2.id

快乐编码！

:)）

Happy Coding!
:)

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