Question

我需要知道表中的最后5个条目是否由相同的用户ID放置（在用户ID下面的代码中是frozen_by。

这就是我所拥有的

//count if the last 5 freezes was placed by the same user

$strFind="SELECT COUNT(*) AS `total` FROM `contest_frozen` WHERE `contest_id`=\"$pid\" AND `frozen_by`=\"$curmemid\" ORDER BY `id` DESC LIMIT 5";
$result=mysql_query($strFind) or die(mysql_error());
$row=mysql_fetch_array($result);
$freeze_total=$row['total'];

if($freeze_total>=5){
//do this
}

if($freeze_total<5){
//do this
}

Answer 1

您可以使用如下查询：它返回最后5行中不同用户的数量。它还返回最高的用户ID，因此如果UserCount == 1和MaxUser == $curmemid，则您知道该用户放置了最后五个记录。

SELECT
  count(distinct frozen_by) as UserCount,
  max(frozen_by) as MaxUser
FROM 
  contest_frozen
WHERE 
  contest_id = $pid 
ORDER BY 
  `id` DESC 
LIMIT 5

如果您需要明确的计数，您也可以这样做。下面的查询返回给定用户的记录数和其他用户的记录数。如果ThisUserCount == 5则所有5条记录都来自该用户。

SELECT
  sum(case when frozen_by = $curmemid then 1 else 0 end) as ThisUserCount,
  sum(case when frozen_by = $curmemid then 0 else 1 end) as OtherUserCount

FROM 
  contest_frozen
WHERE 
  contest_id = $pid 
ORDER BY 
  `id` DESC 
LIMIT 5

在最近5个结果中计算用户ID

1 个答案: