从哪个表中检索数据

Question

SELECT username,
       password,
FROM table1
WHERE username = :username
UNION ALL
SELECT username,
       password,
FROM table2
WHERE username = :username

我想从table1或table2中找到从哪个表中检索的数据 而且，这些表中插入的数据是唯一的

提前致谢

Answer 1

添加包含以下信息的列：

SELECT 'table1' as which, username, password
FROM table1
WHERE username = :username
UNION ALL
SELECT 'table2' as which, username, password
FROM table2
WHERE username = :username;