為什么使用我的 SELF-JOIN 會出錯？

Question

select 1.jmeno, 1.nadr
from zam as 1,
    zam as 2
where 1.nadr = 2.nadr
group by 1.jmeno, 1.nadr;

Answer 1

您需要更改表的別名

select a1.jmeno, a1.nadr
from zam as a1 join
    zam as a2
on a1.nadr = a2.nadr
group by a1.jmeno, a1.nadr

Answer 2

使用以字母開頭的別名並使用顯式連接而不是逗號分隔連接

select t1.jmeno, t1.nadr
from zam as t1 join  zam as t2
on t1.nadr = t2.nadr

因為您的查詢中沒有聚合，所以我刪除了 group by 而您可以使用distinct