如何选择mysql中的最新条目? [英] How do I select the most recent entry in mysql?
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问题描述
我想从表中选择最新条目,然后查看该条目是否与用户尝试输入的条目完全相同.如何查询以从发布"的最新条目中选择*"?
i want to select the most recent entry from a table and see if that entry is exactly the same as the one the user is trying to enter. How do I do a query to "select * from the most recent entry of 'posting'"?
$query="Select * FROM
//confused here
(SELECT * FROM posting ORDER BY date_added DESC)
WHERE user_id='{$_SESSION['user_id']}'
AND title='$title'
AND price='$price'
AND city='$city'
AND state='$state'
AND detail='$detail'
";
$data = mysqli_query($dbc, $query);
$row = mysqli_fetch_array($data);
if(mysqli_num_rows($data)>0)
{
echo "You already posted this ad. Most likely caused by refreshing too many times.";
echo "<br>";
$linkposting_id=$row['posting_id'];
echo "See the <a href='ad.php?posting_id=$linkposting_id'>Ad</a>";
}
else
{
...insert into the dbc
}
//would this query work? or how do i use it to select the last ID in the table 'posting'?
$query="SELECT LAST_INSERT_ID(posting)
WHERE user_id='{$_SESSION['user_id']}'
AND title='$title'
AND price='$price'
AND city='$city'
AND state='$state'
AND detail='$detail'
";
推荐答案
orderby件需要出现在查询的末尾.因此,您要查询的是这样的:
The orderby piece needs to come at the end of your query. So the query you're asking for is something like this:
select * from posting where .... order by date_added desc limit 1;
一次性使用表单令牌也可以帮助防止重复提交.
Single-use form tokens can help prevent duplicate submissions, too.
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