MDAC 2.5 SDK - ODBC Programmer's Reference
Chapter 8: SQL Statements

LIKE Predicate Escape Character

In a LIKE predicate, the percent sign (%) matches zero or more of any character and the underscore (_) matches any one character. To match an actual percent sign or underscore in a LIKE predicate, an escape character must precede the percent sign or underscore. The escape sequence that defines the LIKE predicate escape character is

{escape 'escape-character'}

where escape-character is any character supported by the data source.

For more information on the LIKE escape sequence, see "LIKE Escape Sequence" in Appendix C, "SQL Grammar."

For example, the following SQL statements create the same result set of customer names that start with the characters "%AAA". The first statement uses the escape-sequence syntax. The second statement uses the native syntax for Microsoft® Access and is not interoperable. Note that the second percent character in each LIKE predicate is a wildcard character that matches zero or more of any character.

SELECT Name FROM Customers WHERE Name LIKE '\%AAA%' {escape '\'}

SELECT Name FROM Customers WHERE Name LIKE '[%]AAA%'

To determine whether the LIKE predicate escape character is supported by a data source, an application calls SQLGetInfo with the SQL_LIKE_ESCAPE_CLAUSE option.