Re: State of the support for the hstore ? operator

Thomas Kellerer wrote:
> I just stumbled upon this (using postgresql-9.4-1205.jdbc42.jar)
> 
>   Statement stmt = con.createStatement();
>   ResultSet rs = stmt.executeQuery("select count(*) from product where attributes ? 'location_id'");
> 
> results in
> 
>    org.postgresql.util.PSQLException: ERROR: syntax error at or near "$1"
> 
> "product.attributes" is a hstore column:
> 
> I recall a discussion about this problem a while ago, but I can't find it any more.
> 
> While I certainly would expect a problem when using a PreparedStatement I am surprised
> that a "plain" executeQuerys() also tries to do parameter replacement.
> 
> I have found the suggestion to use exist(attributes, 'location_id') but that is not
> an option as that does not use the index on the column.
> 
> So what is the state of this? Do we have a way of escaping the ? operator?
> 
> I couldn't find anything in the documentation.

I looked into the source, and you can escape the question mark by doubling it.

But I agree that it is strange that the JDBC driver substitutes question marks
with positional parameters in that case.

I think that is a bug in org/postgresql/core/Parser: Even if "withParameters"
is false, it parses question marks.

I'll try to come up with a patch.

Yours,
Laurenz Albe