How to improve my natural language search query - mysql

Question

I have a query I am trying to build which I want to dose some natural language searching. I am unsure of the best way to do this in mysql. I believe mysql has some cool natural language stuff that I can use.
I have two tables which I have shown below.
1. transaction_category...
+--------------------+--------------------+-------------------+----------+
| tran_category_code | tran_category_desc | tran_category_seq | btn_type |
+--------------------+--------------------+-------------------+----------+
| CarParking | Car Parking | 2 | default |
| Electricity | Electricity | 1 | default |
| Groceries | Groceries | 4 | default |
| HealthInsurance | Health Insurance | 5 | default |
| Other | Other | 7 | default |
| Petrol | Petrol | 3 | default |
| Phone | Phone | 6 | default |
+--------------------+--------------------+-------------------+----------+
2. transaction_category_keyword...
+---------------------------------+------------------------------+--------------------+
| transaction_category_keyword_id | transaction_category_keyword | tran_category_code |
+---------------------------------+------------------------------+--------------------+
| 6 | Telstra | Phone |
| 7 | Park | CarParking |
| 8 | Coles | Groceries |
| 9 | Bp Connect | Petrol |
| 10 | Bupa | HealthInsurance |
+---------------------------------+------------------------------+--------------------+
My query is below and that returns the results I want but I was just wondering if anyone could give me advice on whether this could be improved using mysql's natural language functions. This would help me because the search is very simple now but I will be building on it a lot soon.
SELECT
tck.transaction_category_keyword_id,
tck.transaction_category_keyword,
tck.tran_category_code
FROM transaction_category tc, transaction_category_keyword tck
WHERE tc.tran_category_code = tck.tran_category_code
AND 'Coles Menai Syd Au' like '%' ||UPPER(tck.transaction_category_keyword) || '%'
+---------------------------------+------------------------------+--------------------+
| transaction_category_keyword_id | transaction_category_keyword | tran_category_code |
+---------------------------------+------------------------------+--------------------+
| 7 | Park | CarParking |
| 8 | Coles | Groceries |
| 10 | Bupa | HealthInsurance |
| 9 | Bp Connect | Petrol |
| 6 | Telstra | Phone |
+---------------------------------+------------------------------+--------------------+
thanks

Answer 1

In general, if you have a wildcard at both the beginning and end of your search field, then your searches are going to be fairly slow on any non-trivial table sizes, as the field will have to be searched starting from every index.
You would definitely benefit from full text search and match as you are searching for bags of words (and their relative frequencies in the index), rather than a specific string within some other field. I assume you have read the docs at http://dev.mysql.com/doc/refman/5.0/en/fulltext-search.html. There are a number of subtleties you need to understand such as stop words, boolean search, query expansion, etc. The comments on these pages are very good as they have the accumulated knowledge of people who have been there before and experimented.
It is also worth reading about tf-idf which is how MySQL (and many other full-text searches) work internally, see the docs, wich basically ranks a search according to a combination of how rare a word is in all documents and how many times is occurs in a particular document.
I can't give you any more focused examples, or performance metrics, as your question is asking will full text outperform a double wildcard like search, to which the answer is a pretty much unqualified yes.
CAVEAT: Always worth mentioning, given the differences between engines, but before MySQL version 5.6 full-text search only words for MyISAM, but thereafter with InnoDB too.