PostgreSQL: Full Text Search - How to search partial words?

Question

Following a question posted here about how I can increase the speed on one of my SQL Search methods, I was advised to update my table to make use of Full Text Search. This i

Answer 1

Anthoni,

Assuming you plan on using only ASCII encoding (could be difficult, I'm aware), a very viable option may be the Trigram (pg_trgm) module: http://www.postgresql.org/docs/9.0/interactive/pgtrgm.html

Trigram utilizes built-in indexing methods such as Gist and Gin. The only modification you have to make is when defining your index, specify an Operator Class of either gist_trgm_ops or gin_trgm_ops.

If the contrib modules aren't already installed, in Ubuntu it's as easy and running the following command from the shell:

# sudo apt-get install postgresql-contrib

After the contrib modules are made available, you must install the pg_trgm extension into the database in question. You do this by executing the following PostgreSQL query on the database you wish to install the module into:

CREATE EXTENSION pg_trgm;

After the pg_trgm extension has been installed, we're ready to have some fun!

-- Create a test table.
CREATE TABLE test (my_column text)
-- Create a Trigram index.
CREATE INDEX test_my_colun_trgm_idx ON test USING gist (my_column gist_trgm_ops);
-- Add a couple records
INSERT INTO test (my_Column) VALUES ('First Entry'), ('Second Entry'), ('Third Entry')
-- Query using our new index --
SELECT my_column, similarity(my_column, 'Frist Entry') AS similarity FROM test WHERE my_column % 'Frist Entry' ORDER BY similarity DESC