The ODBC Extended SQL standard provides SQL extensions to ODBC that support the advanced nonstandard SQL feature set offered in both Oracle and SQL Server. This standard allows the ODBC driver to convert generic SQL statements to Oracle- and SQL Server–native SQL syntax.
This standard addresses outer joins, such as predicate escape characters, scalar functions, date/time/timestamp values, and stored programs. This syntax is used to identify these extensions:
--(*vendor(Microsoft), product(ODBC) extension *)--OR{extension}
The conversion takes place at run time and does not require the revision of any program code. In most application development scenarios, the best approach is to write one program and allow ODBC to perform the RDBMS conversion process when the program is run.