Question

我有两张电子邮件和电话号码存储表。这两个表的列shop都引用了shop_id。

我想要的是从id = 1的商店中取出所有电子邮件，然后从同一商店获取电话号码。

SELECT 
    shop_contact_phone.id, 
    shop_contact_phone.shop_id, 
    number, tbl.email
FROM (
    SELECT * 
    FROM shop_contact_email 
    WHERE shop_id = 1
    ) AS tbl
JOIN 
    shop_contact_phone 
ON (shop_contact_phone.shop_id = tbl.shop_id);

但是，我收到了重复的条目。我在这做错了什么？

这是我的sqlfiddle。

Answer 1

如果您想要电话号码和电子邮件的列表，请使用union all代替join：

select sce.shop_id, 'email' as contacttype, sce.email
from shop_contact_email sce
where sce.shop_id = 1
union all
select scp.shop_id, 'phone', scp.number
from shop_contact_phone scp
where scp.shop_id = 1;

这会将它们放在不同的行上。您也可以根据需要将它们聚合成字符串或数组。

为什么我从这个连接语句中得到重复？

1 个答案: