gajendra s v <svgajendra@gmail.com> wrote:
> I have added one column with xml type ,after adding I am getting
> following error.
>
> org.postgresql.util.PSQLException: ERROR: could not identify an equality operator for type xml
The UNION operation requires comparing all columns in the result
record to remove duplicates. To identify duplicates, there must be
a notion of equality defined (getting technical here) by a default
btree opclass for the type. XML does not have one, so UNION of a
result set including an XML column is not allowed.
Do you need the duplicate removal? If not, use UNION ALL. If you
need that you may need to cast the XML to text for intermediate
steps and then cast back to XML at the outermost level.
--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
