Oracle9i SQL Reference Release 2 (9.2) Part Number A96540-02 |
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Like built-in operators, user-defined operators take a set of operands as input and return a result. However, you create them with the CREATE
OPERATOR
statement, and they are identified by names. They reside in the same namespace as tables, views, types, and standalone functions.
Once you have defined a new operator, you can use it in SQL statements like any other built-in operator. For example, you can use user-defined operators in the select list of a SELECT
statement, the condition of a WHERE
clause, or in ORDER
BY
clauses and GROUP
BY
clauses. However, you must have EXECUTE
privilege on the operator to do so, because it is a user-defined object.
For example, if you define an operator includes
, which takes as input a text column and a keyword and returns 1 if the row contains the specified keyword, you can then write the following SQL query:
SELECT * FROM product_descriptions WHERE includes (translated_description, 'Oracle and UNIX') = 1;
See Also:
CREATE OPERATOR and Oracle9i Data Cartridge Developer's Guide for more information on user-defined operators |