php - 从 MYSQL - PHP 获取日期范围内的记录

Question

我下面有一个 MYSQL 表，我正在尝试检索特定日期之间的记录数。

我收到以下错误:

'Trying to get property 'num_rows' of non-object in /var/www/html/dev/timeTest.php on line 18'

MySQL表的日期列:

PHP:

 $date1 = '2018-07-01';
 $date2 = '2018-07-30';

 $sql = "SELECT * FROM scanUploads WHERE dateUpload BETWEEN {$date1} AND {$date2}";
 $result = $mysqli -> query($sql);
 $count = $result -> num_rows; // LINE 18
 echo 'records: '.$count;

Answer 1

您缺少引号，这会破坏语法。

而且大括号对我来说也很奇怪。

有两种方式来表达它，要么用' 分隔查询字符串，要么用":

$sql = 'SELECT * FROM scanUploads WHERE dateUpload BETWEEN "'.$date1.'" AND "'.$date2.'"';
$sql = "SELECT * FROM scanUploads WHERE dateUpload BETWEEN \"$date1\" AND \"$date2\"";

// whenever wondering about the validity of generated SQL:
// die($sql);

// and whenever wondering about the result-set returned:
// die(print_r($result, true));

转义双引号 \" 将始终按字面处理，但仅在 "" 双引号内。