DROP DATABASE IF EXISTS mcs173_db;
CREATE DATABASE mcs173_db;
USE mcs173_db;
SET default_storage_engine=Columnstore;
CREATE TABLE t1 (a CHAR(1), b INT, c DATETIME, d DOUBLE);
INSERT INTO t1 VALUES ('', 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=latin1
SELECT COALESCE(NULL, NULL, NULL, 'mariadb', NULL, 'columnstore');
COALESCE(NULL, NULL, NULL, 'mariadb', NULL, 'columnstore')
mariadb
SELECT COALESCE(NULL, 1, 2, 'columnstore');
COALESCE(NULL, 1, 2, 'columnstore')
1
SELECT a, COALESCE(a, 'na') FROM t1;
a	COALESCE(a, 'na')
NULL	na
a	a
b	b
c	c
d	d
SELECT b, COALESCE(b, 'null value') FROM t1;
b	COALESCE(b, 'null value')
NULL	null value
12	12
13	13
14	14
15	15
SELECT d, COALESCE(d, 'null value') FROM t1;
d	COALESCE(d, 'null value')
NULL	null value
1.19691e100	1.19691e100
2.1961e18	2.1961e18
0.16191	0.16191
1.971917	1.971917
DROP DATABASE mcs173_db;