A SQL Escape Sequences
Language features, such as outer joins and scalar function calls, are commonly implemented by database systems. The syntax for these features is often database-specific, even when a standard syntax has been defined. ODBC and JDBC define escape sequences that contain standard syntaxes for the language features in Table A-1.
NOTE: The .NET data provider supports ODBC/JDBC SQL escape sequences, except where otherwise noted.
The escape sequence is recognized and parsed by the driver or data provider, which replaces the escape sequences with data store-specific grammar.