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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.
43 lines
1.2 KiB
Plaintext
43 lines
1.2 KiB
Plaintext
DROP DATABASE IF EXISTS mcs176_db;
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CREATE DATABASE mcs176_db;
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USE mcs176_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 IF(10<20, 1, 2);
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IF(10<20, 1, 2)
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1
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SELECT IF(STRCMP("hello","hi") = 0, "YES", "NO");
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IF(STRCMP("hello","hi") = 0, "YES", "NO")
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NO
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SELECT a, IF(a='b', 10, 20) AS result FROM t1;
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a result
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NULL 20
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a 20
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b 10
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c 20
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d 20
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SELECT b, IF(b<=13, 'Less than or equal to 13', 'Greater than 13') AS result FROM t1;
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b result
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NULL Greater than 13
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12 Less than or equal to 13
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13 Less than or equal to 13
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14 Greater than 13
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15 Greater than 13
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SELECT c, IF(c>0, 'date', 'zero date') AS result FROM t1;
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c result
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0000-00-00 00:00:00 zero date
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1212-12-12 00:00:00 date
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1313-03-13 13:13:13 date
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1414-04-14 00:00:00 date
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2015-05-15 15:15:15 date
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DROP DATABASE mcs176_db;
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