全文索引无法正常工作

Question

this is my first post although I read your threads on a regular base.

The problem I face has to do with the FULLTEXT index on a table of mine. You can see the procedure I followed below:

CREATE TABLE dost(
  author VARCHAR(30),
  title VARCHAR(40),
  isbn SMALLINT NOT NULL)ENGINE MyISAM;

ALTER TABLE dost ADD FULLTEXT(author);

ALTER TABLE dost ADD FULLTEXT(author);

ALTER TABLE dost ADD FULLTEXT(author);

After I inserted some data into the table, it looked something like this:

author                 title                               isbn

Fyodor Dostoyevsky     Poor Folk                           225125
Fyodor Dostoyevsky     Crime and Punishment                121320
Fyodor Dostoyevsky     The Gambler                         124239
Rowan Williams         Dostoyevsky                         083409
Joseph Frank           Dostoyevsky: A Writer In His Time   089823

The problem occurs when I try to use the MATCH AGAINST command to the author column. To be more specific, when I type

SELECT author,title FROM dost WHERE MATCH(author) AGAINST('Williams');

I get the expected result ( Rowan Williams Dostoyevsky ) BUT when I follow the same procedure and change the AGAINST input from 'Williams' to 'Dostoyevsky' it outputs an empty set as a result. On the other hand, the FULLTEXT index on the title column works fine. Any ideas why this problem is caused?

Thanks for your time!

Answer 1

You're doing what is called a natural language search. In this type of search, any word that is in 50% or more of the rows will be ignored as a "common value." Reference .

If that limitation isn't what you want, then you'll need to do a boolean full-text search instead, like this:

SELECT author,title FROM dost WHERE MATCH(author) AGAINST('+Dostoyevsky' IN BOOLEAN MODE);