php - 从mysql中的表中获取最大值

Question

我想从按party_id 分组的表中获取或获取最大日期。

为此，我尝试了：

$check = mysql_fetch_array(mysql_query("select max(fixed_date) as f from case_proceeding group by party_id where party_id='$row[party_id]'"));

之后，我想像这样打印最大日期：

echo $check['f'];

但它不起作用。我认为 mysql_query 有错误。

score 0 · Accepted Answer

尝试，GROUP BY（应该在WHERE子句之后）在这里不需要，因为你已经从WHERE

$check = mysql_fetch_array(mysql_query("select max(fixed_date) as f from case_proceeding where party_id='$row[$party_id]'"));

但是您的查询很容易受到攻击SQL Injection，请阅读下面的文章以防止它

score 0 · Accepted Answer

试试这个：

此处不需要 GROUP BY 子句

select max(fixed_date) as f 
from   case_proceeding 
where  party_id='$row[party_id]

score 0 · Accepted Answer

试试这个：：

select max(DATE(fixed_date)) as f from case_proceeding where party_id=? group by party_id

score 0 · Accepted Answer

尝试

$check = mysql_fetch_array(mysql_query("select max(fixed_date) as f from case_proceeding where party_id='$row[party_id]' "));

注意：mysql_* 函数已弃用，因此请尝试 pdo 或 mysqli

4 回答 4