function ts_rank_cd(text, tsquery) does not exist

问题

I'm using full text search supported by postgres, I installed acts_as_tsearch plugin and it works successfully, but when I tried it later I found an error

runtimeError: ERROR C42883 Mfunction ts_rank_cd(text, tsquery) does not exist HNo function matches the given name and argument types. You might need to add explicit type

回答1:

You need to cast your first parameter into a tsvector.

So let's assume you're searching against a column named foo.text. You will want to change from this:

SELECT ts_rank_cd(foo.text, plainto_tsquery('my search terms')) FROM foo;

to this:

SELECT ts_rank_cd(to_tsvector(foo.text), plainto_tsquery('my search terms')) FROM foo;

or something similar.

If you're using the @@ operator elsewhere, you can generally re-use the expressions that operator is operating on.

You can find more documentation on to_tsvector at http://www.postgresql.org/docs/current/static/textsearch-controls.html#TEXTSEARCH-PARSING-DOCUMENTS

回答2:

EDIT

ts_rank_cd(text, tsquery) does not exist

This means there is no function with this name that accepts text and a tsquery parameter as input. And that's correct, PostgreSQL doens't have a function using these parameters.

From the manual:

ts_rank_cd([ weights float4[], ] vector tsvector, query tsquery [, normalization integer ])

Change your input for the function ts_rank_cd() and you will be fine.

来源：https://stackoverflow.com/questions/3501831/function-ts-rank-cdtext-tsquery-does-not-exist