java 中操作数应包含 1 列

Question

String  sql = "SELECT (Employee_name, Password) FROM employee WHERE (Employee_name = '"+name+"'  AND Password = '"+password+"')";

并在 JSP java.sql.sqlexception insert operand should contains 1 columns(s) 中出现以下异常

请帮忙。

Answer 1

正确的方法是

String  sql = "SELECT Employee_name, Password FROM employee WHERE Employee_name = '"+name+"'  AND Password = '"+password+"'";

您可以保留()for where 子句，但不能保留在选择列表中。这就是你的情况发生的情况

mysql> select (firstname,email) from users limit 1 ;
ERROR 1241 (21000): Operand should contain 1 column(s)