Re: BUG #8211: Syntax error when creating index on expression - Mailing list pgsql-bugs

acizov@gmail.com writes:
> CREATE INDEX heuristic ON foos (1 / (a + b))
> causes:
> ERROR:  syntax error at or near "1"

This is not a bug.  You need an extra pair of parentheses around
the expression, ie

CREATE INDEX heuristic ON foos ((1 / (a + b)))

http://www.postgresql.org/docs/9.2/static/sql-createindex.html
points this out both in the syntax diagram and the text.

            regards, tom lane