我正在尝试使用PDO在PHP中运行查询。
查询在顶部有一些变量来确定等级,但是当在$sql中使用SET @var时,它返回一个空行集。但是,如果我删除有问题的SQL,则返回正常。
我不想在我的脚本中返回@prev_value,@rank_count或@rank_increasing,只想返回在SELECT中创建的等级。
请告诉我我做错了什么?
谢谢
$sql = "
SET @prev_value = NULL;
SET @rank_count = 0;
SET @rank_increasing = 0;
SELECT a.*
, @rank_increasing := @rank_increasing + 1 AS row_num
, CASE
WHEN @prev_value = score
THEN @rank_count
WHEN @prev_value := score
THEN @rank_count := @rank_increasing
END AS rank
FROM (
-- INLINE VIEW --
) a
";
try {
$sth = $dbh->prepare($sql);
$sth->execute(array($var1, $var2));
return $sth->fetchAll(PDO::FETCH_ASSOC);
} catch (Exception $e) {
return $e;
}