how to select 2 table using join?

[weiwei]

I have 2 table here whicjh is list of item and iteminformation, how can i combine this two table usnig join?

$sql = mysql_query("SELECT FROM listofitem WHERE ID='$id'");
$sql1=mysql_query("SELECT FROM iteminformation WHERE ID='$id'");

[void_function]

Well, first you need a field in listofitem that holds unique ID of row from iteminformation (or vice versa, depends on the many-to-one, or one-to-one, relationship direction)

Let's say that ID is primary key in listofitem, and item_id holds the primary key, ID, of the item in iteminformation.

SELECT t1.whatever, t2.whatever2 FROM listofitem AS t1 LEFT JOIN iteminformation AS t2 ON t1.item_id=t2.id WHERE whereclause_if_any

You will get two columns (for above example) with second column NULL if no association was found. This dictates the "order" of joining, depending on what your data logic is. The most often used order is in many-to-one relationships where you select from "many" and join the "one" for additional info on the "many".

For simple join, and it WILL NOT show rows where association is missing (note that you use up WHERE to do actual join):

SELECT t1.whatever, t2.whatever2 FROM listofitem AS t1, iteminformation AS t1 WHERE t1.item_id=t2.id

I hope this makes sense.