有一表产品表(product)如下:id name code
1 a 101
2 a 101
3 a 101
4 x 101
5 b 103
6 b 103
7 z 103
8 c 106
9 m 106
10 c 106要求把同code 不同name 记录列出下结果
name code
a 101
x 101
b 103
z 103
c 106
m 106
1 a 101
2 a 101
3 a 101
4 x 101
5 b 103
6 b 103
7 z 103
8 c 106
9 m 106
10 c 106要求把同code 不同name 记录列出下结果
name code
a 101
x 101
b 103
z 103
c 106
m 106
select distinct name,code from product;
--或
select name,code from product group by name,code;
from pyk a,pyk b
where a.code=b.code and a.name<>b.name
order by a.code
2.数据库优化中明确提过 尽量不用distinct 最好用group by 替代所以根据你的数据 可以这样:select name,code,avg(code) from product group by name,code;
select unique a.name,a.code from product a,product b where a.name<>b.name and a.code=b.code;