USE tpch1;
drop table if exists testnulldate;
create table testnulldate (id int, time_stamp datetime) engine=columnstore;
insert into testnulldate values (1, '2010-11-08 17:46:44');
insert into testnulldate values (2, null);
insert into testnulldate values (3, SUBDATE('2010-11-08 17:46:44', 1));
select
id,
`time_stamp`,
DATE(`time_stamp`) as `Date`,
case when `time_stamp` is null then 'N/A' else DATE(`time_stamp`) end as
`Test1`,
ifnull((DATE(`time_stamp`)),'N/A') as `Test2`,
if(`time_stamp` is null, 'N/A', DATE(`time_stamp`)) as `Test3`,
if(`time_stamp`<='2010-11-08 17:46:44',DATE(`time_stamp`),'N/A') as `Test4`,
if(`time_stamp`<='2010-11-08 17:46:44',DATE(`time_stamp`),DATE('2010-11-08 17:46:44')) as `Test5`
from testnulldate;
id	time_stamp	Date	Test1	Test2	Test3	Test4	Test5
1	2010-11-08 17:46:44	2010-11-08	2010-11-08	2010-11-08	2010-11-08	2010-11-08	2010-11-08
2	NULL	NULL	N/A	N/A	N/A	N/A	2010-11-08
3	2010-11-07 17:46:44	2010-11-07	2010-11-07	2010-11-07	2010-11-07	2010-11-07	2010-11-07
select
id,
`time_stamp`,
YEAR(`time_stamp`) as `Date`,
case when `time_stamp` is null then 'N/A' else YEAR(`time_stamp`) end as
`Test1`,
ifnull((YEAR(`time_stamp`)),'N/A') as `Test2`,
if(`time_stamp` is null, 'N/A', YEAR(`time_stamp`)) as `Test3`,
if(`time_stamp`<='2010-11-08 17:46:44',YEAR(`time_stamp`),'N/A') as `Test4`,
if(`time_stamp`<='2010-11-08 17:46:44',YEAR(`time_stamp`),DATE('2010-11-08 17:46:44')) as `Test5`
from testnulldate;
id	time_stamp	Date	Test1	Test2	Test3	Test4	Test5
1	2010-11-08 17:46:44	2010	2010	2010	2010	2010	2010
2	NULL	NULL	N/A	N/A	N/A	N/A	2010-11-08
3	2010-11-07 17:46:44	2010	2010	2010	2010	2010	2010
select
id,
case when `time_stamp` is null then 'N/A' end as `Test1`
from testnulldate;
id	Test1
1	NULL
2	N/A
3	NULL
drop table if exists testnulldate;