$re = '/(\s|\()like(\s|\))\s*\((\'((\w|%|\'{2})]*)\')\s*\+\s?@p\d+\s*\+(\'%\')\)/i';
$str = 'where ( i like \'b\' ) and concat(a,b) like (\'%\'+@p2+\'%\')
a + \'b\' like (\'%\'+@p2+\'%\')
concat(a,b) like (\'%\'+@p2+\'%\') or ltrim(a) like (\'%\'+@p2+\'%\')
select * from a where concat(a,b) like \'a\' and c like d or ltrim(a) like (\'%\'+@p2+\'%\')';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php