Db2 11.1

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CREATE TABLE F_USERS
     (USE_NAME   VARCHAR(48) NOT NULL,
      USE_PARTNER_LINK FLOAT NOT NULL,
      PRIMARY KEY(USE_NAME))
INSERT INTO F_USERS (USE_NAME,USE_PARTNER_LINK)
VALUES('user1', 20),('user2', 25),('user3', 30)
SELECT * from F_USERS


USE_NAME
USE_PARTNER_LINK


user1
20

user2
25

user3
30


CREATE FUNCTION FuncTest1 ()
	RETURNS TABLE
	(
		USE_NAME VARCHAR(48),
		USE_PARTNER_LINK FLOAT
	)
		LANGUAGE SQL
	    MODIFIES SQL DATA
	    DETERMINISTIC
	    BEGIN
	    DECLARE GLOBAL TEMPORARY TABLE USE_TRUNC
		(
	       USE_NAME VARCHAR(48) NULL,
	       USE_PARTNER_LINK FLOAT NULL
		);
	    INSERT INTO SESSION.USE_TRUNC
	    	(USE_NAME,USE_PARTNER_LINK)
		SELECT USE_NAME,USE_PARTNER_LINK FROM F_USERS;
	RETURN
	SELECT USE_NAME,USE_PARTNER_LINK FROM F_USERS;
	END
[IBM][CLI Driver][DB2/LINUXX8664] SQL0104N  An unexpected token "USE_NAME" was found following "ERS;  RETURN  SELECT".  Expected tokens may include:  "(".  LINE NUMBER=20.  SQLSTATE=42601 SQLCODE=-104