PHP way to execute SQL LIKE matching without a database query?

Question

I want to match an input string to my PHP page the same way a match done by the LIKE command in SQL (MySQL) for consistency of other searches. Since (I have seen but don't comprehend) some of the PHP syntax includes SQL commands I am wondering if this is possible?

The reason for this is I am now implementing a search of a keyword versus fields in the DB that are stored in a serialized array, which I have to unserialize in PHP and search depending on the structure of the array. I can't query against the table, just need the matching ability of the query. Otherwise I need to find an alternate matching routine, which won't be consistent. I can't go back and re-structure the DB since this wasn't anticipated wayyy back in the spec. Yes, I need an ugly hack, but am looking for the most elegant.

If it's not possible I could use any recommendation of matching user typed text as a keyword against stored text.

EDIT (for clarification): my main problem is I don't have a thorough grasp on how the LIKE command works (just copying the code) and as the keyword implies some degree of vagueness, I would like that vagueness preserved if I switch to a regular expression. I am better with regex's just not so good with like. My query is "LIKE 'matchme%'"

Answer 1

Update

Based on tomalak's comment and OIS's brilliant idea to use preg_grep, this might be something more along the lines of a final solution for you.

<?php

function convertLikeToRegex( $command )
{
    return "/^" . str_replace( '%', '(.*?)', preg_quote( $command ) ) .  "$/s";
}

function selectLikeMatches( $haystack, $needle )
{
    return preg_grep( convertLikeToRegex( $needle ), $haystack );
}

$likeClauses = array(
    '%foo'
    ,'foo%'
    ,'%foo%'
);

$testInput = array(
    'foobar'
    ,'barfoo'
    ,'barfoobaz'
);

foreach ( $likeClauses as $clause )
{
    echo "Testing $clause:";
    echo '<pre>';
    print_r( selectLikeMatches( $testInput, $clause ) );
    echo '</pre>';
}

Original Post Below

Is this along the lines of what you're after?

<?php

function convertLikeToRegex( $command )
{
    return "/^" . str_replace( '%', '(.*?)', $command ) .  "$/s";
}

$likeClauses = array(
    '%foo'
    ,'foo%'
    ,'%foo%'
);

$testInput = array(
    'foobar'
    ,'barfoo'
    ,'barfoobaz'
);

foreach ( $testInput as $test )
{
    foreach ( $likeClauses as $clause )
    {
        echo "Testing '$test' against like('$clause'): ";
        if ( preg_match( convertLikeToRegex( $clause ), $test ) )
        {
            echo 'Matched!';
        } else {
            echo 'Not Matched!';
        }
        echo '<br>';
    }
    echo '<hr>';
}