Tds_fdw is a PostgreSQL foreign data wrapper that can connect to databases that
use the Tabular Data Stream (TDS) protocol, such as Sybase databases and
Microsoft SQL server. The current version does not yet support JOIN push-down, 
or write operations. It does support WHERE and column pushdowns when
match_column_names is enabled.

WWW: https://github.com/tds-fdw/tds_fdw