Query two tables

datona

I am trying to figure out how I can query two different tables to get a count (?) variable.

Table 1
ID | ip_address | user_id

Table 2

unique_id | user_id | friend | other_variables

I need to query and find all (multiple lines) in Table 2 where user_id = '$user_id'

Then query Table 1 to find if user_id = $friend

I need to get one variables back.

1: How many lines (times) was $friend found in Table 1

Table 1 is updated all the time (users online type thing)
What I have is a 'Friends' list that it needs to see if my friends are online and if so, how many?

Any help and/or coding would be greatly appreciated.
Thanks

laserlight

I'm puzzled as to what is $friend
Also, what is table 1 and table 2?
I presume table 1 is the online users list, primary key ID and foreign key user_id; however, is table 2 a users list or a friends list?
What is there both a unique_id and a user_id if it is a users list?
What does the table2.friend field contain?

datona

Table1 is usersonline
Table2 is my friends table

What I am attempting to do is check the usersonline to see if any of my friends are currently online. If so I would like to out:
You have 'xx' friends currently online.

John_Canyon

SELECT * FROM table1 as t1, table2 as t2 WHERE t1.id=t2.id GROUP BY t1.id

$sql = mysql_query("SELECT * FROM table1 as t1, table2 as t2 WHERE t1.id=t2.id GROUP BY t1.id");

Assuming table1 is your friends table, and table2 is usersonline.
I am assuming you are relating the 2 tables with an identical key.

Then users online would simply be.

mysql_num_rows($sql);

Cheers

datona

Thanks John Canyon,

Works like a charm!

I just can not believe this forum. I have never met anyone (As of yet) that tells you to go read a book!