SQL方言参考

CREATE FUNCTION function_name
  (input_parameter_name datatype, ...)
RETURNS return_type
BEGIN
   /* SQL code */
END

VALUES function_name(...)

or

SELECT function_name(...) FROM ... WHERE function_name(...) = ...

CREATE [ OR REPLACE ] FUNCTION function_name
  (input_parameter_name datatype, ...)
RETURNS return_type   /* return type can also be a table structure */
BEGIN
   /* SQL code */
END


CREATE [ OR REPLACE ] FUNCTION function_name
  (input_parameter_name datatype, ...)
RETURNS return_type   /* return type can also be a table structure */
LANGUAGE {</span> <span class="k">C</span> <span class="o">|</span> <span class="n">CPP</span> <span class="o">|</span> <span class="n">R</span> <span class="o">|</span> <span class="n">PYTHON3</span> <span class="o">|</span> <span class="n">PYTHON3_MAP</span> <span class="err">}
{</span>
   <span class="n">function_body_in_language_syntax</span>
<span class="err">}


CREATE [ OR REPLACE ] FUNCTION function_name
  (input_parameter_name datatype, ...)
RETURNS return_type   /* return type can also be a table structure */
EXTERNAL NAME  MAL_function_name

SELECT function_name(...)

/* when the return type of the function is a table, following is allowed */
SELECT ... FROM function_name(...)

DELIMITER $$

CREATE FUNCTION function_name
  (input_parameter_name datatype, ... )
RETURNS datatype
BEGIN
RETURN
  /* SQL code */
END$$

DELIMITER ;

SELECT function_name(...)

CREATE FUNCTION function_name
  (input_parameter_name datatype, ...)
RETURNS datatype
AS $$
DECLARE
  variable_name datatype;
BEGIN
  /* SQL code */
END;
$$ LANGUAGE plpgsql;

SELECT function_name(...)

DECLARE EXTERNAL FUNCTION function_name [datatype, ...]
RETURNS datatype
ENTRY_POINT 'entryname'
MODULE_NAME 'modulename';

SELECT function_name(...)

CREATE OR REPLACE my_function(p_contract IN VARCHAR2, p_org_id IN VARCHAR2)
RETURN DATE
AS
  l_ret_eff_date DATE := SYSDATE;
BEGIN
  RETURN l_ret_eff_date;
END;
/

SELECT my_function('PARM1', 'ORG1')
FROM dual;