Get total records from 3 tables with one query

[eevan79]

Can I get total records from 3 tables with one query?

 

This is my 3 queries:

$result = mysql_query("SELECT * FROM ".$table_prefix."posts");
$result2 = mysql_query("SELECT * FROM ".$table_prefix."topics");
$result3 = mysql_query("SELECT * FROM ".$table_prefix."users");

 

And to get number of rows I use

$topics = mysql_num_rows($result2);
$posts = mysql_num_rows($result)-$topics;
$users = mysql_num_rows($result3);

 

Can I do this with one query?

[abdfahim]

Something like this.

Let say, 1st table has a column name t1_col1, 2nd table has a column name t2_col1, 3rd table has a column name t3_col1,

$result = mysql_query("SELECT `t1_col1` as `col` FROM ".$table_prefix."posts UNION SELECT `t2_col1` as `col`  FROM ".$table_prefix."topics UNION SELECT `t3_col1` as `col`  FROM ".$table_prefix."users");
$topics = mysql_num_rows($result);

[eevan79]

Thanks for reply.

 

Ok, I select all records with one query, but how to get total rows for each table?

 

$topics = mysql_num_rows($result);

Thats result for all tables.

 

What is with posts and users separately?

[fenway]

Stop -- don't ever use *, throw away all of the data, and just get a count.  That's what COUNT(*) is for.