添加“字段"从 UNION 到 SQL 结果的表名? [英] Add "field" of table name to SQL results from UNION?

问题描述

如果我有一个简单的联合

If I have a simple union

select name, phone from users union select name, phone from vendors;

有没有办法将表名添加到结果中?

Is there a way to add the table name to the results?

所以代替

+--------+-------+
| name   | phone |
+--------+-------+
| Jim    | 123...|
| Macy's | 345...|
+--------+-------+

我会的

+--------+-------+---------+
| name   | phone | table   |
+--------+-------+---------+
| Jim    | 123...| users   |
| Macy's | 345...| vendors |
+--------+-------+---------+

推荐答案

select name, phone, 'users' as table_name from users
union
select name, phone, 'vendors' as table_name from vendors;

更好的解决方案是使用union all，这样服务器就不会检查不同的值

Better solution will be to use union all, so server will not be checking for distinct values

select name, phone, 'users' as table_name from users
union all
select name, phone, 'vendors' as table_name from vendors;

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