Question

在mysql数据库中如何让某个字段有重复的只取一条

表table_a 有4条数据

id A B C D
01 ab 1a2 1b2 121
02 ab 2a3 3b3 4a1
03 ac 1a2 1b2 121
04 ac 2a4 3b2 52g

如何让A字段有重复的只取一条 比如
01 ab 1a2 1b2 121
03 ac 1a2 1b2 121

Answer 1

select * from table_a group by A order by id DESC;

Answer 2

select * from table_a group by A