[Sqlalchemy-tickets] Issue #3160: postgresql - to_tsquery docs and implementation detail (zzzeek/sqlalchemy)

[jvanasco <iss...@bi...>]

New issue 3160: postgresql - to_tsquery docs and implementation detail
https://bitbucket.org/zzzeek/sqlalchemy/issue/3160/postgresql-to_tsquery-docs-and

jvanasco:

I recently realized some implementation details of `to_tsquery` that are incompatible with the docs I drafted and how sqlalchemy integrates it.

Not sure how to handle this.

I based the docs/examples on existing tests and text.  So we have this as the first bit of "Full Text Search"  ( http://docs.sqlalchemy.org/en/latest/dialects/postgresql.html#full-text-search )

    select([sometable.c.text.match("search string")])
    SELECT text @@ to_tsquery('search string') FROM table

well, if we put this into psql...

    badsql=> select to_tsquery('search string') ;
    ERROR:  syntax error in tsquery: "search string"

that's because tsquery has a rigid enforcement of input.  text must either be tokenized and joined with acceptable operators :

    select to_tsquery('cat & rat');

be quoted :

    select to_tsquery('''search string''');

or use the alternate function

    select plainto_tsquery('search string');

So, these are acceptable:
    select to_tsquery('search & string');
    select to_tsquery('''search string''');
    select plainto_tsquery('search string');

but this is not:

    select to_tsquery('search string');

I'm not sure the best way to handle this nuance in the docs.