DROP DATABASE IF EXISTS test_empty_strings;
CREATE DATABASE test_empty_strings;
USE test_empty_strings;
CREATE TABLE t(s text) ENGINE=COLUMNSTORE;
INSERT INTO t(s) VALUES (''), (NULL);
SELECT COUNT(*) FROM t WHERE s IS NULL;
COUNT(*)
1
SELECT COUNT(*) FROM t WHERE s IS NOT NULL;
COUNT(*)
1
SELECT * FROM t;
s

NULL
DROP TABLE t;
CREATE TABLE t(s text) ENGINE=COLUMNSTORE;
INSERT INTO t(s) VALUES ('');
INSERT INTO t(s) VALUES (NULL);
SELECT * FROM t;
s

NULL
SELECT COUNT(*) FROM t WHERE s IS NULL;
COUNT(*)
1
DROP TABLE t;
CREATE TABLE t(s text) ENGINE=COLUMNSTORE;
INSERT INTO t(s) VALUES ('_CpNuLl_'),(''), (NULL);
SELECT * FROM t;
s
_CpNuLl_

NULL
SELECT COUNT(*) FROM t WHERE s IS NULL;
COUNT(*)
1
DROP TABLE t;
CREATE TABLE t(c6 CHAR(6)) ENGINE=COLUMNSTORE;
INSERT INTO t(c6) VALUES ('a'), ('b'), ('c');
SELECT 2, COUNT(*) FROM t WHERE (c6 <= 'b' OR c6 <= '');
2	COUNT(*)
2	2
SELECT 2, COUNT(*) FROM t WHERE (c6 <= 'b');
2	COUNT(*)
2	2
SELECT 0, COUNT(*) FROM t WHERE (c6 <= '');
0	COUNT(*)
0	0
SELECT 0, COUNT(*) FROM t WHERE (c6 <= ' ');
0	COUNT(*)
0	0
SELECT 2, COUNT(*) FROM t WHERE (c6 <= 'b' OR c6 <= ' ');
2	COUNT(*)
2	2
SELECT 0, COUNT(*) FROM t WHERE (c6 < '');
0	COUNT(*)
0	0
SELECT 0, COUNT(*) FROM t WHERE (c6 < ' ');
0	COUNT(*)
0	0
DROP TABLE IF EXISTS t;
CREATE TABLE t(a CHAR(10)) ENGINE=COLUMNSTORE;
INSERT INTO t(a) VALUES (''), (NULL), ('   '), (' a ');
SELECT LTRIM_ORACLE(a) FROM t;
LTRIM_ORACLE(a)
NULL
NULL
NULL
a
SELECT RTRIM_ORACLE(a) FROM t;
RTRIM_ORACLE(a)
NULL
NULL
NULL
 a
DROP DATABASE test_empty_strings;