mysql中的声明值基于特定条件

Question

我想要设置req_status = "UNDONE"。我是否正确地在sql中声明了？我是新人。它表示警告：mysql_fetch_array()期望参数1为资源，布尔值在

中给出

 $res = mysql_query("SELECT * FROM request WHERE req_user = '$un',req_status = 'UNDONE' ORDER BY req_status DESC,req_important ASC,req_dateReceive DESC ");

Answer 1

您收到此错误是因为您的查询无法执行，因为其中存在错误。

您必须使用SELECT WHERE或AND在OR中区分条件。

$res = mysql_query("SELECT * FROM request WHERE req_user = '$un',req_status = 'UNDONE' ORDER BY req_status DESC,req_important ASC,req_dateReceive DESC ");
                                                                ^

更改为

$res = mysql_query("SELECT * FROM request WHERE req_user = '$un' AND req_status = 'UNDONE' ORDER BY req_status DESC,req_important ASC,req_dateReceive DESC ");
                                                                  ^

Answer 2

$res = mysql_query("
                    SELECT * 
                    FROM request 
                    WHERE req_user = '$un' 
                    AND req_status = 'UNDONE' 
                    ORDER BY req_status DESC,
                    req_important ASC,
                    req_dateReceive DESC 
                                            ");

逗号绝对不能使用语法。尝试使用AND。

expects parameter 1 to be resource, boolean given in

意味着PHP期望返回某种形式的资源（如数组），但在查询失败时它返回false。

另外，请不要使用mysql，因为它已被弃用，并且已经存在更安全的方法来防止 SQL注入（了解有关PDO或mysqli的更多信息）

Answer 3

用

替换上面的内容

  $res = mysql_query("SELECT * FROM request WHERE req_user = '$un' AND req_status = 'UNDONE' ORDER BY req_status DESC,req_important ASC,req_dateReceive DESC ");