Date 在php中查询时，找不到正确的值

我有一个“shop”脚本，我想显示sql数据库中的收入值，但我不知道我做错了什么，因为我得到了相同的值：(

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哦，我自己想出了这个：(

及

<?php 
$x = date('d'); 
$res = $db->query("SELECT sum(amount) FROM orders WHERE SUBSTRING(date,6,2) = '$x' AND address != 'NONE' AND method='Bitcoin' OR method='PerfectMoney'"); 
$cols = $res->fetch_row(); 
echo "$".$cols[0]; 
?>

<?php 
$mth = date('m'); 
$res = $db->query("SELECT sum(amount) FROM orders WHERE SUBSTRING(date,9,2) = '$mth' AND address != 'NONE' AND method='Bitcoin' OR method='PerfectMoney'"); 
$cols = $res->fetch_row(); 
echo "$".$cols[0]; 
?>

SUBSTRING(date,6,2) = '$x'"); changed this one to 
SUBSTRING(date,9,2) = '$x'");

SUBSTRING(date,9,2) = '$mth'"); and this one to
SUBSTRING(date,6,2) = '$mth'");