902                  

    1 record(s) selected.

A.4  Sample code for GREATEST function

Example A 17 is a set of UDF examples emulating the behavior of MySQL's 

GREATEST function. The various UDFs accept input parameters in 

varchar 

and 

from 2 to 10 input parameters.

Example: A 17   User defined functions to map GREATEST

   DB2 UDB UDF(User Defined Function) Samples for Migration

   2001/08/28, 08/29

   Name of UDF: GREATEST (P1 VarChar(254), P2 VarChar(254), ...)

   Used UDF: None

   Description: Returns greatest value of list of data.

   Author: TOKUNAGA, Takashi

CREATE FUNCTION GREATEST (P1 VarChar(254), P2 VarChar(254))

 RETURNS VarChar(254)

 LANGUAGE SQL

 SPECIFIC GREATESTOracle2

 DETERMINISTIC

 CONTAINS SQL

 NO EXTERNAL ACTION

 RETURN 

CASE

WHEN P1 >= P2 THEN P1

ELSE               P2

END

;

   GREATEST function with three parameters

CREATE FUNCTION GREATEST (P1 VarChar(254), P2 VarChar(254), P3 VarChar(254))

 RETURNS VarChar(254)

346 

MySQL to DB2 UDB Conversion Guide