PHP PDO：参数号无效

Question

$ emptyNumbers有2个项目，$ qMarks是“？，？”。有什么问题？

if(($key = array_search($row['nummer'], $emptyNumbers)) !== false) {
unset($emptyNumbers[$key]);
}
echo sizeof($emptyNumbers)."==>".$qMarks;  // 2 ==> ?,?
$qMarks = str_repeat('?,', count($emptyNumbers)-1) . '?';
$getPlayerData=$db->prepare( "SELECT number,surname,firstname,position,job FROM player WHERE nummer IN ($qMarks)");         
$getPlayerData->execute($emptyNumbers);

--> Error: PDOStatement::execute(): SQLSTATE[HY093]: Invalid parameter number: parameter was not defined

Answer 1

问题是我之前从$ emptyNumbers中取消了值，并且我没有对数组重新排序，因此存在空值。

if(($key = array_search($row['nummer'], $emptyNumbers)) !== false) {
unset($emptyNumbers[$key]);
//delete the gaps in the array!
$emptyNumbers = array_values($emptyNumbers);
}

$qMarks = str_repeat('?,', count($emptyNumbers)-1) . '?';
$getPlayerData=$db->prepare( "SELECT number,surname,firstname,position,job FROM player WHERE nummer IN ($qMarks)");         
$getPlayerData->execute($emptyNumbers);