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

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>';
}

Answer 2

What you need is preg_grep actually.
$arr = array("tstet", "duh", "str");
$res = preg_grep("#st#i", $arr); //i for case insensitive
var_dump($res);
results in
array(2) {
[0]=>
string(5) "tstet"
[2]=>
string(3) "str"
}
edit:
the user supplies the text, I add the
wildcards behind the scenes. I do use
one %. LIKE 'text%'
here is how you specify it in regex
"#st#i" regex is the same as in sql "%st%"
"#^st#i" regex is the same as in sql "st%"
"#st$#i" regex is the same as in sql "%st"
Also, remember to use preg_quote on any text you get from a third party.
$regex = "#" . preg_quote($text) . "#i";
$res = preg_grep($regex, $arr);

Answer 3

I'd think you'd need preg_match but that's not exactly the same behavior as a LIKE.
<?php // The "i" after the pattern delimiter indicates a case-insensitive search
if (preg_match("/php/i", "PHP is the web scripting language of choice.")) {
echo "A match was found.";
} else {
echo "A match was not found."; }
?>

Answer 4

Do you mean you want to be able to check if the input string is LIKE var% ?
You could use strpos(haystack, needle) to match %var%.
if( strpos($source, "var") == 0 ) echo "matches var%";
if( strlen($source) - (strpos($source, "var")) == strlen("var") ) echo "matches %var";
That is pretty ugly. And actually probably not the most elegant.