mirror of
https://github.com/mariadb-corporation/mariadb-columnstore-engine.git
synced 2025-05-02 19:24:47 +03:00
b53c231ca6
This patch improves handling of NULLs in textual fields in ColumnStore. Previously empty strings were considered NULLs and it could be a problem if data scheme allows for empty strings. It was also one of major reasons of behavior difference between ColumnStore and other engines in MariaDB family. Also, this patch fixes some other bugs and incorrect behavior, for example, incorrect comparison for "column <= ''" which evaluates to constant True for all purposes before this patch.
113 lines
2.2 KiB
Plaintext
113 lines
2.2 KiB
Plaintext
DROP DATABASE IF EXISTS mcs171_db;
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CREATE DATABASE mcs171_db;
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USE mcs171_db;
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SET default_storage_engine=Columnstore;
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CREATE TABLE t1 (a CHAR(1), b INT, c DATETIME, d DOUBLE);
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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);
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SHOW CREATE TABLE t1;
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Table Create Table
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t1 CREATE TABLE `t1` (
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`a` char(1) DEFAULT NULL,
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`b` int(11) DEFAULT NULL,
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`c` datetime DEFAULT NULL,
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`d` double DEFAULT NULL
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) ENGINE=Columnstore DEFAULT CHARSET=latin1
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SELECT IFNULL(NULL, 'abc');
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IFNULL(NULL, 'abc')
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abc
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SELECT IFNULL(NULL, 123);
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IFNULL(NULL, 123)
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123
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SELECT IFNULL('abc', 123);
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IFNULL('abc', 123)
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abc
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SELECT ISNULL(NULL);
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ISNULL(NULL)
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1
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SELECT ISNULL(1);
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ISNULL(1)
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0
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SELECT ISNULL('a');
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ISNULL('a')
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0
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SELECT NULLIF(1, 1);
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NULLIF(1, 1)
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NULL
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SELECT NULLIF('abc', 'a');
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NULLIF('abc', 'a')
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abc
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SELECT NULLIF(1, 'abcd');
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NULLIF(1, 'abcd')
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1
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SELECT a, ISNULL(a) FROM t1;
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a ISNULL(a)
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NULL 1
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a 0
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b 0
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c 0
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d 0
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SELECT b, ISNULL(b) FROM t1;
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b ISNULL(b)
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NULL 1
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12 0
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13 0
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14 0
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15 0
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SELECT c, ISNULL(c) FROM t1;
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c ISNULL(c)
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0000-00-00 00:00:00 0
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1212-12-12 00:00:00 0
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1313-03-13 13:13:13 0
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1414-04-14 00:00:00 0
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2015-05-15 15:15:15 0
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SELECT d, ISNULL(d) FROM t1;
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d ISNULL(d)
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NULL 1
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1.19691e100 0
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2.1961e18 0
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0.16191 0
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1.971917 0
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SELECT a, IFNULL(a, 'Null Char') FROM t1;
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a IFNULL(a, 'Null Char')
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NULL Null Char
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a a
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b b
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c c
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d d
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SELECT b, IFNULL(b, 'Null Integer') FROM t1;
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b IFNULL(b, 'Null Integer')
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NULL Null Integer
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12 12
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13 13
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14 14
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15 15
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SELECT c, IFNULL(d, 'Null Decimal') FROM t1;
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c IFNULL(d, 'Null Decimal')
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0000-00-00 00:00:00 Null Decimal
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1212-12-12 00:00:00 1.19691e100
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1313-03-13 13:13:13 2.1961e18
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1414-04-14 00:00:00 0.16191
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2015-05-15 15:15:15 1.971917
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SELECT a, NULLIF(a, 'c') FROM t1;
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a NULLIF(a, 'c')
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NULL NULL
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a a
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b b
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c NULL
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d d
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SELECT b, NULLIF(b, 15) FROM t1;
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b NULLIF(b, 15)
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NULL -2147483648
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12 12
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13 13
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14 14
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15 NULL
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SELECT c, NULLIF(c, '2015-5-15') FROM t1;
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c NULLIF(c, '2015-5-15')
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0000-00-00 00:00:00 0000-00-00 00:00:00
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1212-12-12 00:00:00 1212-12-12 00:00:00
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1313-03-13 13:13:13 1313-03-13 13:13:13
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1414-04-14 00:00:00 1414-04-14 00:00:00
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2015-05-15 15:15:15 2015-05-15 15:15:15
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DROP DATABASE mcs171_db;
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