使用 IN 指令搜索准备好的语句

Question

我的目的是查找表中与存储在字符串中的集合匹配的所有项目：

$array=array("item1","item2","item3","item4");//This is dynamically filled, this is just an example
$in_list = "'".implode("','",$array)."'";//that's why i use implode

$stmt = $this->db->prepare('SELECT libelle,activite,adresse,tel,lat,lng FROM etablissements where type IN ('.$in_list.')');

        $stmt->bind_param("s", $in_list);
        $stmt->execute();
        $stmt->bind_result($libelle,$activite,$adresse,$tel,$lat,$lng);

这似乎并不完美，它总是向我抛出以下警告：

mysqli_stmt::bind_param() [<a href='mysqli-stmt.bind-param'>mysqli-stmt.bind-param</a>]: Number of elements in type definition string doesn't match number of bind variables in <b>/homepages/25/d399726988/htdocs/

如果我有一个参数，那就很明显了：

    $stmt = $this->db->prepare('SELECT libelle,activite,adresse,tel,lat,lng FROM etablissements where type =?');
$stmt->bind_param("s", $parameter);

但由于我必须处理它，这对我来说变得有点复杂。

Answer 1

准备好的语句没有参数，因为您在准备之前已将列表插入到语句中。

$array=array("item1","item2","item3","item4");
//This is dynamically filled, this is just an example
$in_list = "'".implode("','",$array)."'";//that's why i use implode

$stmt = $this->db->prepare('SELECT libelle,activite,adresse,tel,lat,lng FROM etablissements where type IN ('.$in_list.')');

此时，您创建的SQL语句为：

SELECT libelle,activite,adresse,tel,lat,lng 
FROM etablissements where type IN ('item1','Item2','Item3','Item4')

由于语句没有参数，mysqli_stmt::bind_param 失败。不要将项目插入到语句中（这很容易被注入），而是插入一串参数，然后绑定值（必须分开）。

$array=array("item1","item2","item3","item4");

if (count($in_list) > 0) {
    $query = $this->db->prepare('SELECT libelle,activite,adresse,tel,lat,lng FROM etablissements WHERE type IN (' . str_repeat('?, ', count($in_list)-1) . '?)');

    $args = $in_list;
    array_unshift($args, str_repeat('s', count($in_list)));
    call_user_func_array(array($query, 'bind_param'), $args);
    $query->execute();
    $query->bind_result($libelle,$activite,$adresse,$tel,$lat,$lng);
}

PDO 的绑定接口更直接。

$array=array("item1","item2","item3","item4");

if (count($in_list) > 0) {
    $query = $this->db->prepare('SELECT libelle,activite,adresse,tel,lat,lng FROM etablissements WHERE type IN (' . str_repeat('?, ', count($in_list)-1) . '?)');

    foreach ($in_list as $i => $arg) {
        // query params are 1-based, so add 1 to the index
        // PDO::PARAM_STR is the default type, so no need to pass 3rd arg
        $query->bindValue($i+1, $arg);
    }
    $query->execute();
    // no need to bind the result
}

实际上，使用 PDO 可以更简单，因为PDOStatement::execute 可以获取参数值列表：

$array=array("item1","item2","item3","item4");

if (count($in_list) > 0) {
    $query = $this->db->prepare('SELECT libelle,activite,adresse,tel,lat,lng FROM etablissements WHERE type IN (' . str_repeat('?, ', count($in_list)-1) . '?)');

    $query->execute($in_list);
}