DROP DATABASE IF EXISTS mcs174_db;
CREATE DATABASE mcs174_db;
USE mcs174_db;
SET default_storage_engine=Columnstore;
CREATE TABLE t1 (a CHAR(1), b INT, c DATETIME, d DOUBLE);
INSERT INTO t1 VALUES (NULL, NULL, '0-0-0', NULL),('a', 12, '1212-12-12', 1.19691E+100),('b', 13, '1313-3-13 13:13:13', 2.1961E+18),('c', 14, '1414-4-14', 0.16191),('d', 15, '2015-5-15 15:15:15', 1.971917);
SHOW CREATE TABLE t1;
Table	Create Table
t1	CREATE TABLE `t1` (
  `a` char(1) DEFAULT NULL,
  `b` int(11) DEFAULT NULL,
  `c` datetime DEFAULT NULL,
  `d` double DEFAULT NULL
) ENGINE=Columnstore DEFAULT CHARSET=utf8mb3 COLLATE=utf8mb3_general_ci
SELECT b, c, (CASE WHEN a = 'b' THEN b ELSE c END) FROM t1;
b	c	(CASE WHEN a = 'b' THEN b ELSE c END)
NULL	0000-00-00 00:00:00	0000-00-00 00:00:00
12	1212-12-12 00:00:00	1212-12-12 00:00:00
13	1313-03-13 13:13:13	13
14	1414-04-14 00:00:00	1414-04-14 00:00:00
15	2015-05-15 15:15:15	2015-05-15 15:15:15
SELECT b, a, (CASE WHEN b > 13 THEN b ELSE a END) FROM t1;
b	a	(CASE WHEN b > 13 THEN b ELSE a END)
NULL	NULL	NULL
12	a	a
13	b	b
14	c	14
15	d	15
SELECT c, a, (CASE WHEN d > 1  THEN a ELSE c END) FROM t1;
c	a	(CASE WHEN d > 1  THEN a ELSE c END)
0000-00-00 00:00:00	NULL	0000-00-00 00:00:00
1212-12-12 00:00:00	a	a
1313-03-13 13:13:13	b	b
1414-04-14 00:00:00	c	1414-04-14 00:00:00
2015-05-15 15:15:15	d	d
SELECT a, c, (CASE WHEN c IS NULL THEN a ELSE c END) FROM t1;
a	c	(CASE WHEN c IS NULL THEN a ELSE c END)
NULL	0000-00-00 00:00:00	0000-00-00 00:00:00
a	1212-12-12 00:00:00	1212-12-12 00:00:00
b	1313-03-13 13:13:13	1313-03-13 13:13:13
c	1414-04-14 00:00:00	1414-04-14 00:00:00
d	2015-05-15 15:15:15	2015-05-15 15:15:15
SELECT (CASE WHEN a = 'a' THEN 0 ELSE 1 END) FROM t1;
(CASE WHEN a = 'a' THEN 0 ELSE 1 END)
1
0
1
1
1
SELECT (CASE WHEN 10 > 5 THEN 'True' ELSE 'False' END);
(CASE WHEN 10 > 5 THEN 'True' ELSE 'False' END)
True
DROP DATABASE mcs174_db;