DB2 group by with NULL SQL 错误 [22007]

Question

I have query with data format. I try to convert it into an integer, but it doesn't help me, I can't group by because I have NULL in rows.

SELECT t."Reception Date", CASE WHEN t."DT" IS NULL THEN 100
                                ELSE 100500
                           END AS "GG" 
FROM fit t
GROUP BY t."Reception Date", CASE WHEN t."DT" IS NULL THEN 100
                                  ELSE 100500
                             END

I have many rows so I want to group it, but got error

SQL Error [22007]: [SQL0181] Value in date, time, or timestamp string not valid. java.sql.SQLException: [SQL0181] Value in date, time, or timestamp string not valid.

Reception Date  GG
20160921        100500
20160921        0

SAMPLE DATA:

create table qtemp/fit
(
    "Reception Date" char(10),
    "DT" int
);

insert into qtemp/fit values
('20160921', 140816),
('20160921', 250816),
('20160921', 180816),
('20160921', 70916),
('20160921', 10916),
('20160921', 210916),
('20160921', 210916),
('20160921', 210916),
('20160921', 200916),
('20160921', 0),
('20160921', 0),
('20160921', 0),
('20160921', 0),
('20160921', 0),
('20160921', 210916)

Answer 1

With Sample Date (Assumed):

create table qtemp/tstdta 
(
    "Reception Date" char(10),
    "DT" int
);

insert into qtemp/tstdta values
('20160921', 140816),
('20160921', 250816),
('20160921', 180816),
('20160921', 70916),
('20160921', 10916),
('20160921', 210916),
('20160921', 210916),
('20160921', 210916),
('20160921', 200916),
('20160921', 0),
('20160921', 0),
('20160921', 0),
('20160921', 0),
('20160921', 0),
('20160921', null),
('20160921', null),
('20160921', null)

Solution:

WITH as t (
    SELECT "Reception Date",
          CASE WHEN "DT" IS NULL THEN 100
               ELSE 100500
               END AS "GG"
     FROM qtemp/tstdta
) 
SELECT "Reception Date", "GG", count(*) as COUNT
FROM t
GROUP BY "Reception Date", "GG"

Result:

 Reception Date  GG           COUNT        
 ------------------------------------------
 20160921        100          3             
 20160921        100500       14