如果我有一个简单的工会
select name, phone from users union select name, phone from vendors;
有没有一种方法可以将表名添加到结果中？
所以代替
+--------+-------+ | name | phone | +--------+-------+ | Jim | 123...| | Macy's | 345...| +--------+-------+
我会
+--------+-------+---------+ | name | phone | table | +--------+-------+---------+ | Jim | 123...| users | | Macy's | 345...| vendors | +--------+-------+---------+
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，因此服务器将不会检查不同的值
union all
select name, phone, 'users' as table_name from users union all select name, phone, 'vendors' as table_name from vendors;
