Question

I have 2 tables an item_key table and a paypal_ipn_orders table. In item_key I store item names and a *sort_id* which is an 8 digit number I use to sort the items, in the paypal_ipn_orders table I have an item name as well as a *sort_id*.

What happens

1. an order comes into> paypal_ipn_orders with an ITEM name
2. a query executes on the item_key table checking for a matching ITEM name in the table
3. If a match exists it assigns its 8 digit value(item_key.SORT_ID) to paypal_ipn_orders.SORT_ID

I know how to cross reference the tables to find matching records when they are identical however not all if not most item titles have a slight variance ie extra spaces, a number 4 instead of 1, a the or extra character.

Query
UPDATE paypal_ipn_orders
SET sort_num = (SELECT sort_id
FROM itemkey
WHERE itemkey.item = paypal_ipn_orders.item_name)
WHERE LOWER(payment_status) = 'completed' 

Result

table: paypal_ipn_orders
ITEM                                SORT_ID
4 Icy Manipulator ~ Ice Age         NULL
4 Worldslayer - Mirrodin MtG Magic  NULL
1 Karn Liberated - New Phyrexia MtG NULL
4 Blightning ~ Shards               12334234(identical title= a non-null SORT_ID)

table: item_key
ITEM                                SORT_ID
1 Icy Manipulator + Ice Age         12334231(doesnt exactly match)
4 Worldslayer - Mirrodin Magic      12334332(doesnt exactly match)
4 Karn Liberated - Phyrexia MtG     12334333(doesnt exactly match)
4 Blightning ~ Shards               12334234(perfect match)

Desired Result

table: paypal_ipn_orders
ITEM                                SORT_ID
4 Icy Manipulator ~ Ice Age         12334231(similar title = match assign value)
4 Worldslayer - Mirrodin MtG Magic  12334232(similar title = match assign value)
1 Karn Liberated - New Phyrexia MtG 12334233(similar title = match assign value)
4 Blightning ~ Shards               12334234(exact title = match assign value)

Answer 1

Please read about Levenshtein distance. Maybe this might help you.

DELIMITER $$
CREATE FUNCTION levenshtein( s1 VARCHAR(255), s2 VARCHAR(255) ) 
  RETURNS INT 
  DETERMINISTIC 
  BEGIN 
    DECLARE s1_len, s2_len, i, j, c, c_temp, cost INT; 
    DECLARE s1_char CHAR; 
    -- max strlen=255 
    DECLARE cv0, cv1 VARBINARY(256); 
    SET s1_len = CHAR_LENGTH(s1), s2_len = CHAR_LENGTH(s2), cv1 = 0x00, j = 1, i = 1, c = 0; 
    IF s1 = s2 THEN 
      RETURN 0; 
    ELSEIF s1_len = 0 THEN 
      RETURN s2_len; 
    ELSEIF s2_len = 0 THEN 
      RETURN s1_len; 
    ELSE 
      WHILE j <= s2_len DO 
        SET cv1 = CONCAT(cv1, UNHEX(HEX(j))), j = j + 1; 
      END WHILE; 
      WHILE i <= s1_len DO 
        SET s1_char = SUBSTRING(s1, i, 1), c = i, cv0 = UNHEX(HEX(i)), j = 1; 
        WHILE j <= s2_len DO 
          SET c = c + 1; 
          IF s1_char = SUBSTRING(s2, j, 1) THEN  
            SET cost = 0; ELSE SET cost = 1; 
          END IF; 
          SET c_temp = CONV(HEX(SUBSTRING(cv1, j, 1)), 16, 10) + cost; 
          IF c > c_temp THEN SET c = c_temp; END IF; 
            SET c_temp = CONV(HEX(SUBSTRING(cv1, j+1, 1)), 16, 10) + 1; 
            IF c > c_temp THEN  
              SET c = c_temp;  
            END IF; 
            SET cv0 = CONCAT(cv0, UNHEX(HEX(c))), j = j + 1; 
        END WHILE; 
        SET cv1 = cv0, i = i + 1; 
      END WHILE; 
    END IF; 
    RETURN c; 
  END$$
  DELIMITER ;

Helper function:

DELIMITER $$
CREATE FUNCTION levenshtein_ratio( s1 VARCHAR(255), s2 VARCHAR(255) ) 
  RETURNS INT 
  DETERMINISTIC 
  BEGIN 
    DECLARE s1_len, s2_len, max_len INT; 
    SET s1_len = LENGTH(s1), s2_len = LENGTH(s2); 
    IF s1_len > s2_len THEN  
      SET max_len = s1_len;  
    ELSE  
      SET max_len = s2_len;  
    END IF; 
    RETURN ROUND((1 - LEVENSHTEIN(s1, s2) / max_len) * 100); 
  END$$
  DELIMITER ;