Having issues with max() and mysql/php

[Anon]

Hi there,

I posted about this a while ago but it was a slightly different problem... I have approached it a different way and am still having issues. 🙁 If someone could help me out I would forever be indebted.

I want to pull out the highest article # according to author, depending upon department.

When I use this below and query the db, this works:

$sql = "SELECT max(Articles.ar_id), Articles.ar_author
FROM Articles
WHERE Articles.ar_dept = $dept
GROUP BY Articles.ar_author";
$sqlResult = mysql_query($sql);

---

Now, what I want to do is take the max(Articles.ar_id) and convert it to a variable, so I can query the db again in order to get other information out (Articles.ar_article, Articles.ar_title)

But, I cannot figure out how to get the article # from max(Articles.ar_id)

I tried pulling it out of $sqlResult using mysql_fetch_array and mysql_fetch_object but both times I get a blank variable for $maxArticleID. This is the code:

while ($articleRow = mysql_fetch_array($sqlResult)) {
$maxArticleID = $articleRow["Articles.ar_id"];
print($maxArticleID);
}

Why is it coming up blank? Am I doing this all wrong?

[mithril]

Michelle,

The name of the array for the Articles.ar_id field in your example is actually "max(Articles.ar_id)". Thus you can either access the value using that field name (unweildly) or, modify your SQL statement like so:

"max(Articles.ar_id) AS ar_id"

Now the returned field name is "ar_id" which is much nicer🙂 A third method is to use the numerical index returned by mysql_fetch_array()...... unless specified otherwise, mysql_fetch_array() returns both associative and numerical array indices. Since "max(Articles.ar_id)" is the first field, it's numerical index is [0]. HTH,

Cheers,

Geoff A. Virgo