我正试图通过计算开始日期和结束日期之间自动整数（id）的出现次数来按日期范围计算登录次数。
我从上一页的表格中得到开始日期和结束日期（y-m-d）。
$start_date=$_POST['start_date']; /*in this case its "2014-10-10"*/
$end_date=$_POST['end_date']; /*in this case its "2014-10-20"*/
$sql = <<<SQL
SELECT id, COUNT(*) as login_count FROM `usage`
GROUP BY id
WHERE date
BETWEEN $start_date AND $end_date
SQL;
然而，我不断得到以下语法错误
"运行查询时出错[您的SQL语法有错误；请查看与MySQL服务器版本相对应的手册，以获取在第3行的'WHERE date BETWEEN 2014-10-10 AND 2014-10-20'附近使用的正确语法]"
我做错了什么？
try it
$sql = <<<SQL
SELECT id, COUNT(*) as login_count FROM `usage`
WHERE date
BETWEEN '$start_date' AND '$end_date'
GROUP BY id
SQL;
您的$sql应该是：
$sql = <<<SQL
SELECT id, COUNT(*) as login_count FROM `usage`
WHERE date
BETWEEN $start_date AND $end_date
GROUP BY id
SQL;
因为GROUP BY CLAUSE在语法上是AFTER WHERE
您需要将''放在sql中的日期文字周围，如下所示：
$response = mysql_query("SELECT * FROM `db`.`$sql_table` WHERE (date BETWEEN '$end_date' AND '$start_date') ORDER by id ASC ")or die(mysql_error());
首先，您应该引用日期'$start_date'和'$end_date'，并且您应该确保对这些值进行转义以避免SQL注入。
您的SQL中有错误。试试这个：
SELECT id, COUNT(*) as login_count FROM `usage`
WHERE (date BETWEEN $start_date AND $end_date)
GROUP BY id;