MySQL - alternative for like - regexp? - mysql

Question

i have got over one milion record in my database table.
When I use like is very slowly, when i use match against they lost some records.
I create help table:
tag_list
tag_id
tag_name
tag_rel_message
tag_id
messag_id
messages
message_id
message_text
in tag_list i add all words of $message_text - explode(" ", $message_text);
My new query is:
SELECT m.*
FROM tag_rel_messages trm
INNER JOIN messages m ON (trm.message_id = m.message_id)
INNER JOIN tag_list tl ON (trm.tag_id=tl.tag_id
WHERE tl.tag_name REGEXP 'pionas' AND tl.tag_name REGEXP 'website'
GROUP By trm.message_id
But not display any records.
What's wrong with this query?
Maybe i should use something other than REGEXP?
Thanks for help

Answer 1

I'm not sure how one column could match two things at the same time! You can use OR in place of AND, or you can use a single call to REGEXP.
SELECT m.*
FROM tag_rel_messages trm
INNER JOIN messages m ON (trm.message_id = m.message_id)
INNER JOIN tag_list tl ON (trm.tag_id=tl.tag_id
WHERE tl.tag_name REGEXP 'pionas|website'
GROUP By trm.message_id

Answer 2

You need to join with the tag_list and tag_rel_message tables twice to match two different tags.
SELECT m.*
FROM messages AS m
JOIN tag_rel_messages AS trm1 ON m.message_id = trm1.message_id
JOIN tag_list AS t1 ON t1.tag_id = trm1.tag_id
JOIN tag_rel_messages AS trm2 ON m.message_id = trm2.message_id
JOIN tag_list AS t2 on t2.tag_id = trm2.tag_id
WHERE t1.tag_name = 'pionas' AND t2.tag_name = 'website'
Another way to do it is to join with either tag, and count the number of results per message
SELECT m.*
FROM messages AS m
JOIN tag_rel_messages AS trm ON m.message_id = trm.message_id
JOIN tag_list AS t ON t1.tag_id = trm.tag_id
WHERE t.tag_name IN ('pionas', 'website')
GROUP BY m.message_id
HAVING COUNT(*) = 2
This second form is a little easier to generalize to any number of tags. Put all the tags in the IN clause, and change the HAVING clause to match the number of tags.

Answer 3

$words = array('pionas', 'website');
$tags_id = array();
foreach ($words as $key => $val) {
$sql = "SELECT tag_id FROM tag_list WHERE tag_name LIKE '%".$val."%'";
$records = $db->query($sql);
$tags_id[$key] = array_column($records, "tag_id");
}
$inner_array = array();
foreach ($tags_id as $k => $v) {
$short_name = "trm_".$k;
$inner_array[] = " INNER JOIN tag_rel_message as ".$short_name." ON ( ".$short_name.".message_id = m.message_id AND ".$short_name.".tag_id IN (".implode(", ", $v).")) ";
}
$sql = "SELECT DISTINCT m.* FROM messages m".implode(" ", $inner_array);
I think this is the same:
SELECT * FROM messages WHERE message_text like '%pionas%' AND message_text like '%website%'