Question

I have an application that allow users to search on multiple columns (prod_name,prod_desc)

So I used full text search like below, but it does not return all the records, for excample I tried to find ‘o’ character in 2 columns (prod_name,prod_desc)but it can not find for some records.
Also when I do not use wildcard for the ‘o’ character it can not find any thing while contains means like %o%.
I am a bit confused about full text search.

Please help what is the problem.

CREATE FULLTEXT CATALOG catalog_crashcourse3;

CREATE FULLTEXT INDEX ON products(prod_name,prod_desc)
KEY INDEX pk_products ON catalog_crashcourse3;

SELECT prod_name, prod_desc
FROM products
WHERE CONTAINS((prod_name,prod_desc), '"*o*"');

Answer 1

SQL Server FTS is a word-based search process. When you create a full-text index on a column, the indexing engine crawls the content and breaks it into individual words in a process known as tokenization. The index then stored the word, the primary key of the row it was found in, and the word’s position in the content (i.e. is is the first word in the field, the 57th word, or whatever).

When you specify a CONTAINS predicate such as

CONTAINS((prod_name,prod_desc), '"o"');

the SQL Server FTS engine looks for tokens (i.e. words) in its index that are “o”. If your content does not have the word “o” in it (which is probably doesn’t) then no matches will be found.

As you point out, you can do wildcard searches, where you try and matched patterns in the indexed word. For example, if you specify a predicate such as

CONTAINS((prod_name,prod_desc), '"o*"');

then the search will return all words in the indexed content that start with the letter “o”

FTS is best used when you want to search for groups of words in your indexed content. It can do sophisticated word stemming (such as searching for “ran” and “running” when you specify “run”). It also provides a ranking of the search result content so that you can find the best match. If you just want to search for a specified word in your content and your content is not too large, you may not need FTS. As MikeSmithDev pointed out in the comments, you may be able to just get away with a LIKE clause.

Note added: In response to your comment, if you have a table with 8 columns that you want to search using FTS, then you would create full-text indexes on each of these columns and search them as follows:

CONTAINS(*, '"Word"')

where the asterik indicates that all 8 indexed columns in the table should be included in the search.