The LIKE, REGEXP, and SIMILAR TO search conditions are similar in that they all attempt to match a pattern to a string. Also, all three attempt to match an entire string, not a substring within the string.

The basic syntax for all three search conditions is similar:

expression search-condition pattern

The difference between the LIKE, REGEXP, and SIMILAR TO search conditions lies in what you can specify for pattern. SIMILAR TO syntax for pattern allows a robust pattern matching using the regular expression syntax defined in the ANSI/ISO SQL standard. Regular expressions provide the capability for sophisticated pattern matching.

REGEXP supports a superset of regular expression syntax supported by SIMILAR TO. In addition, the REGEXP search condition supports a number of syntax extensions for compatibility with other products. Also, REGEXP and SIMILAR TO have a different default escape character.

The LIKE syntax for pattern is simple and supports a small set of wildcards, but does not support regular expressions.

For more information about the regular expression syntax supported by the SIMILAR TO and REGEXP search conditions, see Regular expressions.

See also

• Regular expressions
• Regular expression syntax
• Regular expression examples