Hey, I am working on a tutorial system for my site. and right now I have my MySQL Database set up and the pages for it mostly setup (On WAMP).

I have it so it will support categories, For example.Each tutorial gets a field for category, I want to know how to echo just the tutorials with their category set to "1" On a page, So if i want a page for just Photoshop tutorials I get it, And if I want one for just CSS Tutorials I get it.

Can anyone help? Thanks.

SELECT fieldlist FROM table WHERE category_field = number_to_filter_by

PHP Code:

$res = mysql_query("SELECT * FROM table where categories='1' limit 1") 
or die(mysql_error());  

while($row = mysql_fetch_array( $res )) {
echo $row['id'];
echo "<br>"; 
echo $row['categories'];
echo "<br>"; 
} 


You should NOT use SELECT * in REAL queries

Chris, what is the real slowdown of "select *" compared to "select id, name, otherstuff"? I suspect that it is like saving on matches, especially when using joins or selecting from tables with high number of rows.

At the very least it forces an extra pass through the database(s) to get the column names.
But the biggest one is that it will return every column and the data which can be a huge memory hog especially if you only need one or two columns.

Take the query above for example;
returns ALL columns and only uses two of them. Maybe not an issue by itself or for one or two queries several minutes apart.
BUT what if the table has 50 fields? That could be a huge chunk of space that the OS has to reserve in memory as a array, when in reality in may only need 10 bytes per record.
Then scale that up to several queries a minute with a million row table.