php - mysql_fetch_assoc 函数替换

Question

在我的 php 代码中，我有 2 个循环，它们运行正常，除了 1 个 if 语句，我无法替换以下函数。

(1)虽然这段代码很好并且在第一个循环中运行

if(isset($_GET['Filter']) && !empty($_GET['Filter'])){
    $query = "SELECT * FROM Apartment WHERE ";
    foreach( $_GET['Filter'] as $filter ){
        $query .= "$filter='y' AND ";
    }
    $query = substr($query, 0, -5);
}

while($data = mysql_fetch_array( $result )) {
    //echo $data
}

(2)另一个给出了 sql 错误

if(isset($_GET['Filter']) && !empty($_GET['Filter'])){
    $sql = mysql_query("SELECT * FROM Apartment WHERE" );
    foreach( $_GET['Filter'] as $filter ){
        $sql .=("$filter='y' ORDER BY RegularPrice ASC LIMIT 1 AND ");
    }
    $sql = substr($sql, 0, -5);
}

while($row = mysql_fetch_assoc($sql)) {
    //echo $row
}

有人可以帮我找到我发布的第二个 if 语句中最终的语法错误吗？

Answer 1

对于第二个查询，您将部分 mysql_query() 分配给变量 $sql，然后将字符串连接到它。我认为这是一个错误，您只想将字符串 SELECT * FROM Apartment WHERE 分配给变量 $sql。

另外，请注意您要连接的字符串:

$sql = mysql_query("SELECT * FROM Apartment WHERE" );
foreach( $_GET['Filter'] as $filter ){
    $sql .=("$filter='y' ORDER BY RegularPrice ASC LIMIT 1 AND ");
}

这将产生如下内容:

SELECT * FROM Apartment WHERE filter1='y' ORDER BY RegularPrice ASC LIMIT 1 AND filter2='y' ORDER BY RegularPrice ASC LIMIT 1 AND filter3='y' ORDER BY RegularPrice ASC LIMIT 1 AND

这是一个无效的 SQL 查询。

您想尝试什么:

$sql = "SELECT * FROM Apartment WHERE ";
foreach( $_GET['Filter'] as $filter ){
    $sql .= "$filter='y' AND ";
}
$sql = substr($query, 0, -5); // Remove the last ' AND '
$sql .= " ORDER BY RegularPrice ASC LIMIT 1";

$result = mysql_query ($sql);