mysql - 如何结合这两个凭证查询？

Question

我想将这两个查询合并为一个查询。查询的目的是检查“user_credentials”表或“workers”表中的凭据是否匹配。我怎样才能这样做？

SELECT user_name FROM user_credentials WHERE user_name = '$user_email' AND password = '$user_password'

SELECT user_name FROM workers WHERE user_name = '$user_email' AND password = '$user_password'

Answer 1

试试这个

SELECT user_name FROM user_credentials WHERE user_name = '$user_email' AND password = '$user_password'

union

SELECT user_name FROM workers WHERE user_name = '$user_email' AND password = '$user_password'

然后检查mysqli_num_rows或mysql_num_rows