php - SELECT(带 ? 和 $variable)返回空数组

Question

抱歉，我不明白问题出在哪里。

这行得通

$query_select_date = "SELECT * FROM 2013Currencies WHERE DateOfCurrencyRate = '2001-03-23'";
$sql_select_date = $db->prepare($query_select_date);
$sql_select_date->execute();
$data_select_date = $sql_select_date->fetchAll(PDO::FETCH_ASSOC);

但这不起作用(获取空数组)

$query_select_date = "SELECT * FROM 2013Currencies WHERE DateOfCurrencyRate = ?";
$cdate = "'2001-03-23'";// or $cdate = "2001-03-23"; or $cdate = 2001-03-23; result is the same
$sql_select_date->execute($cdate);
$data_select_date = $sql_select_date->fetchAll(PDO::FETCH_ASSOC);

我想有一些错误，但不明白在哪里。

Answer 1

您需要将一个数组传递给执行方法:

$sql_select_date->execute(array($cdate));

希望对你有帮助