Php 如何在mysqli prepare语句中动态使用
我试着在mysqli prepare语句中使用Php 如何在mysqli prepare语句中动态使用,php,mysqli,prepared-statement,Php,Mysqli,Prepared Statement,我试着在mysqli prepare语句中使用 $user_in = "'28','22'"; $stmt = $this->connection->prepare("SELECT `id` FROM `$this->table_name` WHERE `user_id` IN (?) "); if($stmt){ $stmt->bind_param('s',$user_in);
$user_in = "'28','22'";
$stmt = $this->connection->prepare("SELECT `id` FROM `$this->table_name` WHERE `user_id` IN (?) ");
if($stmt){
$stmt->bind_param('s',$user_in);
if($stmt->execute()){
$result = $stmt->get_result();
if($result !== false && $result->num_rows >= 1){
$row = $result->fetch_all(MYSQLI_ASSOC);
$stmt->close();
var_dump($row);
}
}
}
echo $this->connection->error;
return false;
但上述方法无法获取任何结果集,占位符表示单个值。如果您有使用查询的变量和占位符:
$var = '1,2,3';
SELECT ... WHERE foo IN (?)
然后,查询将按照SQL的字面意思执行
SELECT ... WHERE foo IN ('1,2,3')
您的3个单独的csv值将被视为单个整体字符串
在子句中,是占位符有些无用的地方,因为您已经动态地构建了一个字符串,其中占位符的数量与您的值相同,例如
$vals = array(1,2,3);
$placeholders = '?' . str_repeat(',?', count($vals) - 1);
$stmt = $db->prepare("SELECT ... WHERE foo IN ($placeholders)");
foreach($vals as $i => $val) {
$stmt->bind($i, $vals[$i]);
}
然后在mysqli上找到一个更方便的包装器,它提供例如?
Perl样式的数组占位符。