match clause returning incorrect results

Question

I am trying to use FTS3 in sqlite and executing a query which is not returning desired results. here is the query:

select * from table1 where col1 MATCH 'rain';

this query is returning col1 containing text 'strain' too which I do not want. I want the exact replica of this query:

select * from table1 where col1 like '% rain %';

any suggestions/comments/help?

Answer 1

In case of FTS3/FTS4 in sqlite database, I conclude that the default tokenizer which is simple (at least) ignores '(' and ')' while tokenizing the elements in any text column. Other special characters can also be checked as I doubt there would be others too. When the match query is executed, these values were ignored. Here is the test case for my scenario:

create virtual table tab1 using fts3(val text);
insert into tab1 values('this is rain test');
insert into tab1 values('this is strain test');
insert into tab1 values('this is (rain) test with parenthesis');
insert into tab1 values('rain test');
insert into tab1 values('this is rain');
insert into tab1 values('strain test');
insert into tab1 values('this is strain');

after executing the following query:

select * from tab1 where val MATCH 'rain';

results were:

this is rain test
this is (rain) test with parenthesis
rain test
this is rain

Answer 2

I'm unsure why you get this result. You should only get results with matching terms for the MATCH query you posted. Can you post your FTS3 CREATE TABLE statement?

For example:

SQLite version 3.7.11 2012-03-20 11:35:50
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> CREATE VIRTUAL TABLE mail USING fts3(subject, body);
sqlite> INSERT INTO mail(docid, subject, body) VALUES(1, 'software feedback', 'found it too slow');
sqlite> INSERT INTO mail(docid, subject, body) VALUES(2, 'software feedback', 'no feedback');
sqlite> INSERT INTO mail(docid, subject, body) VALUES(3, 'slow lunch order',  'was a software problem');
sqlite> select * from mail where body match 'back';
sqlite> select * from mail where body match 'feedback';
software feedback|no feedback