Best practice to implement blank tile search to anagram solver - php

Question

I currently have an anagram solver on my website that works well and quickly.
I use an array structure to hold number values of each letter used in each word. So basically when someone put in the letters "fghdywkjd" My solver will go through each word in its db and match the amout of letters in each word to the values associated with the letter inputted ie. "fghdywkjd"
I build the array like this
$a = array('a' => 1, 'b' => 1, 'c' => 1, 'd' => 1, 'e' => 1, 'f' => 1, 'g' => 1, 'h' => 1, 'i' => 1, 'j' => 1, 'k' => 1, 'l' => 1, 'm' => 1, 'n' => 1, 'o' => 1, 'p' => 1, 'q' => 1, 'r' => 1, 's' => 1, 't' => 1, 'u' => 1, 'v' => 1, 'w' => 1, 'x' => 1, 'y' => 1, 'z' => 1);
It counts the values as it goes through each word.
I am trying to think of the best way to add a blank tile feature to it that is not going to slow it down.
The only way I can figure out how to add this feature is to wait till I have all my results then take each word found and add the letter "a" and find possibilities, then add the latter "b" and so on. For each word that would be enormous.
Anyways some ideas?

Answer 1

Here's probably how I would do it. I would set up the word database table structure like this: (The main reason for this is speed. We could split the names by letter each query but I think this way is faster though I haven't benchmarked).
name a b c d e f g h i j k l m n o p q r s t u v w x y z
---- - - - - - - - - - - - - - - - - - - - - - - - - - -
test 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 0 0
tests 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 0 0 0 0 0 0
foo 0 0 0 0 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0
and then in the PHP I'd do this: This assumes that the number of letters in the word has to match the anagram exactly (no extra letters).
<?php
$letters = array_fill_keys (range('a', 'z'), 0);
$word = 'set'; // start with the word 'set'
$wordLetters = str_split(preg_replace("/[^a-z]/", '', strtolower($word))); // remove invalid letters, lowercase, and convert to array
$numberOfWildcards = 1; // Change this to the number of wildcards you want
foreach ($wordLetters as $letter) {
$letters[$letter]++;
}
$query = 'SELECT `name`, 0';
foreach ($letters as $letter => $num) {
// $query .= "+ABS(`$letter`-$num)";
$query .= "+IF(`$letter` > $num, `$letter` - $num, 0)";
}
$query = ' AS difference
FROM `word_table`
WHERE
LENGTH(`name`) = ' . (strlen($word) + $numberOfWildcards) . '
HAVING
difference = ' . $numberOfWildcards;
If you want to see the difference between the word you are checking and all the words in the database get rid of the where and having clauses.
Let me know how this works out for you.