How to implement a Keyword Search in MySQL?

Question

I am new to SQL programming.

I have a table job where the fields are id, position, category, location, sala

Answer 1

For a single keyword on VARCHAR fields you can use LIKE:

SELECT id, category, location
FROM table
WHERE
(
    category LIKE '%keyword%'
    OR location LIKE '%keyword%'
)

For a description you're usually better adding a full text index and doing a Full-Text Search (MyISAM only):

SELECT id, description
FROM table
WHERE MATCH (description) AGAINST('keyword1 keyword2')

Answer 2

I know this is a bit late but what I did to our application is this. Hope this will help someone tho. But it works for me:

SELECT * FROM `landmarks` WHERE `landmark_name` OR `landmark_description` OR `landmark_address` LIKE '%keyword'
OR `landmark_name` OR `landmark_description` OR `landmark_address` LIKE 'keyword%' 
OR `landmark_name` OR `landmark_description` OR `landmark_address` LIKE '%keyword%'

Answer 3

You can find another simpler option in a thread here: Match Against.. with a more detail help in 11.9.2. Boolean Full-Text Searches

This is just in case someone need a more compact option. This will require to create an Index FULLTEXT in the table, which can be accomplish easily.

Information on how to create Indexes (MySQL): MySQL FULLTEXT Indexing and Searching

In the FULLTEXT Index you can have more than one column listed, the result would be an SQL Statement with an index named search:

SELECT *,MATCH (`column`) AGAINST('+keyword1* +keyword2* +keyword3*') as relevance  FROM `documents`USE INDEX(search) WHERE MATCH (`column`) AGAINST('+keyword1* +keyword2* +keyword3*' IN BOOLEAN MODE) ORDER BY relevance;

I tried with multiple columns, with no luck. Even though multiple columns are allowed in indexes, you still need an index for each column to use with Match/Against Statement.

Depending in your criterias you can use either options.

Answer 4

Personally, I wouldn't use the LIKE string comparison on the ID field or any other numeric field. It doesn't make sense for a search for ID# "216" to return 16216, 21651, 3216087, 5321668..., and so on and so forth; likewise with salary.

Also, if you want to use prepared statements to prevent SQL injections, you would use a query string like:

SELECT * FROM job WHERE `position` LIKE CONCAT('%', ? ,'%') OR ...

Answer 5

I will explain the method i usally prefer:

First of all you need to take into consideration that for this method you will sacrifice memory with the aim of gaining computation speed. Second you need to have a the right to edit the table structure.

1) Add a field (i usually call it "digest") where you store all the data from the table.

The field will look like:

"n-n1-n2-n3-n4-n5-n6-n7-n8-n9" etc.. where n is a single word

I achieve this using a regular expression thar replaces " " with "-". This field is the result of all the table data "digested" in one sigle string.

2) Use the LIKE statement %keyword% on the digest field:

SELECT * FROM table WHERE digest LIKE %keyword%

you can even build a qUery with a little loop so you can search for multiple keywords at the same time looking like:

SELECT * FROM table WHERE 
 digest LIKE %keyword1% AND 
 digest LIKE %keyword2% AND 
 digest LIKE %keyword3% ... 

Answer 6

SELECT 
    *
FROM 
    yourtable
WHERE 
    id LIKE '%keyword%' 
    OR position LIKE '%keyword%'
    OR category LIKE '%keyword%'
    OR location LIKE '%keyword%'
    OR description LIKE '%keyword%'
    OR refno LIKE '%keyword%';