PHP 和 mysql_query 问题

Question

我有以下 PHP 代码:

$sql = '
SELECT t1.name, t2.code, COUNT(t2.code) as cnt 
FROM t1 
LEFT JOIN t2 
ON t2.code = t1.code2
WHERE (t2.input_date BETWEEN "2015-04-01" AND "2015-04-29") 
AND t2.serial = 5 
GROUP BY t2.code HAVING (t2.code>0)';

$Chartdata= mysql_query($sql) or die(mysql_error()); 
$arr = array();
while ($row = mysql_fetch_assoc($Chartdata)) {
    $arr[] = $row;
}
echo json_encode($arr);

此代码在我的浏览器上显示一个空白页面。我尝试删除最后一个“AND”和“GROUP BY...”，它显示1个值。

Answer 1

尝试一下:

$sql = '
SELECT t1.name, t2.code, COUNT(*) as cnt 
FROM t1 
LEFT JOIN t2 
ON t2.code = t1.code2
WHERE (t2.input_date BETWEEN "2015-04-01" AND "2015-04-29") 
AND t2.serial = 5 
AND t2.code>0
GROUP BY t2.code';