Trouble with text search select statement

Started by Mont Rothsteinabout 18 years ago3 messagesgeneral
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#1Mont Rothstein
mont.rothstein@gmail.com

I am having trouble getting a multiple column text search select statement
to work.

I've setup the following:

CREATE TABLE tstest (col1 text, col2 text);
INSERT INTO tstest (col1, col2) VALUES ('bird', 'moon');
CREATE INDEX tstest_ts_idx ON tstest USING gin(to_tsvector('english',
coalesce(col1, '') || '' || coalesce(col2, '')));

I then execute what I believe is the correct select statement:

SELECT * FROM tstest WHERE to_tsvector('english', coalesce(col1, '') || ''
|| coalesce(col2, '')) @@ to_tsquery('english', 'bird');

If I remove the second column from the to_tsvector in the select statement
then it returns the row.

SELECT * FROM tstest WHERE to_tsvector('english', coalesce(col1, '')) @@
to_tsquery('english', 'bird');

I know I've missed something basic but I can't figure out what.

As a side note I don't understand the purpose of the || '' || between the
columns in the to_tsvector. I saw it in several examples. I've tried both
with and without it with no change.

Thanks in advance.

-Mont

#2Klint Gore
kgore4@une.edu.au
In reply to: Mont Rothstein (#1)
Re: Trouble with text search select statement

Mont Rothstein wrote:

I am having trouble getting a multiple column text search select
statement to work.

I've setup the following:

CREATE TABLE tstest (col1 text, col2 text);
INSERT INTO tstest (col1, col2) VALUES ('bird', 'moon');
CREATE INDEX tstest_ts_idx ON tstest USING gin(to_tsvector('english',
coalesce(col1, '') || '' || coalesce(col2, '')));

I then execute what I believe is the correct select statement:

SELECT * FROM tstest WHERE to_tsvector('english', coalesce(col1, '')
|| '' || coalesce(col2, '')) @@ to_tsquery('english', 'bird');

If I remove the second column from the to_tsvector in the select
statement then it returns the row.

SELECT * FROM tstest WHERE to_tsvector('english', coalesce(col1, ''))
@@ to_tsquery('english', 'bird');

I know I've missed something basic but I can't figure out what.

As a side note I don't understand the purpose of the || '' || between
the columns in the to_tsvector. I saw it in several examples. I've
tried both with and without it with no change.

'' isn't supposed to to be the empty string, it's supposed to be a
quoted space. to_tsvector separates on whitespace. So with the space,
it will have the words bird and moon.Without the space, it will have the
single word birdmoon.

klint.

--
Klint Gore
Database Manager
Sheep CRC
A.G.B.U.
University of New England
Armidale NSW 2350

Ph: 02 6773 3789
Fax: 02 6773 3266
EMail: kgore4@une.edu.au

#3Mont Rothstein
mont.rothstein@gmail.com
In reply to: Klint Gore (#2)
Re: Trouble with text search select statement

Thank you. I knew it had to be something simple.
Much appreciated.

-Mont