SQL查询无法正确构建

Question

我做了一个查询，显示了5个结果，在一个月内有最高的观看次数; 使用静态日期自己的查询工作正常，但是当我尝试使用date()函数获取当前年份和月份时，它不起作用：

$currentmonth = date("m");
$nextmonth = $currentmonth++;
$gethotbookq = mysqli_query($con,"SELECT BookID, COUNT(*) AS `num` FROM `BOOKS_views` WHERE `TIME` >= '2014- $currentmonth-01 00:00:00' and `TIME` < '2014-$nextmonth-01 00:00:00' GROUP BY `BookID` LIMIT 5") or die();

Answer 1

 $currentmonth = date("m");
 $nextmonth    = date("m", strtotime(" +1 month"));
 $gethotbookq  = mysqli_query($con,"SELECT BookID, COUNT(*) AS `num` FROM `BOOKS_views` WHERE `TIME` >= '2014-$currentmonth-01 00:00:00' and `TIME` < '2014-$nextmonth-01 00:00:00' GROUP BY `BookID` LIMIT 5") or die();