从多个表中选择MySQL PHP查询

Question

I have a search script here, that needs to search multiple tables for a phrase/word using MySQL and PHP. The column name column that is being searched is all the same across tables. Any help would be appreciated and here is my code below:

<?php
    $filter = $_REQUEST['query'];
    mysql_connect($hostname,$username, $password) or die ("<script language='JavaScript'>alert('Unable to connect to database! Please try again later.'),history.go(-1)</script>");
    mysql_select_db($dbname);
    $query = 'SELECT * FROM (SELECT `name` FROM `voxmoviesfilestable`) a UNION (SELECT `name` FROM `voxadultfilestable`) b UNION (SELECT `name` FROM `voxmixesfilestable`) c UNION (SELECT `name` FROM `voxconcertsfilestable`) d UNION (SELECT `name` FROM `voxmp3filestable`) e UNION (SELECT `name` FROM `voxfilestable`) WHERE `name` REGEXP \''.$filter.'\' ORDER BY `name`;';
    $maxquery = 'SELECT count(*) as cnt FROM `voxmoviesfilestable`, `voxadultfilestable`, `voxmixesfilestable`, `voxconcertsfilestable`, `voxmp3filestable`, `voxfilestable` WHERE `name` REGEXP \''.$filter.'\';';

    $result = mysql_query($query) or die ('Error accessing Database');
?>

Answer 1

The command "select ... from table1, table2, table3..." does not do what it appears you think it does. It does a massive join of every row of every table to every row of every other table. That is very bad. It looks like you want union. But, it isn't that easy as you must get the columns to look alike. It would look like:

select * from ((select id, name from table1) a union (select id, name from table2) b union ...) where regexp '$filter' order by name

NOTE: I added parenthesis around the union section about 12 hours after initially writing this.

The union will take time, but I believe it would be faster than querying each table separately in PHP.