Question

请问这个SQL语句该怎么写呢？

这里有两个表
表1:table1：
------------------------
| id | name | flag |
| 1 | a | 1 |
| 2 | b | 1 |
| 3 | c | 2 |
-----------------------------------------------------
表2:table2
----------------------------------------
| id | name | demp |
| 1 | a | 1-1 |
| 2 | a | 1-2 |
| 3 | b | 1-1 |
-------------------------------------------------------
如何查询，表1中flag为1，然后对应相同name的表2中的demp。
想要的结果是：
--------------------------------------------------
| name | demp |
| a | 1-1 |
| a | 1-2 |
| b | 1-1 |
------------------------------------------
谢谢了。

Answer 1

select t2.name,t2.demp
from table1 as t1
inner join table2 as t2 on t1.name=t2.name
where t1.flag=1
参考下

Answer 2

select table2.name,table2.demp
from table1,table2
where table1.name=table2.name
and table1.flag=1

Answer 3

select name，demp from table2 where name in（select name from table1 where flag=1）

Answer 4

select name , demp from table1 , table2 where table1.flag=1 and table1.name=table2.name

Answer 5

select t1.name, t2.demp from table1 t1, table2 t2
where substr(t2.demp, 1, 1) = t1.flag