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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.
47 lines
975 B
Plaintext
47 lines
975 B
Plaintext
DROP DATABASE IF EXISTS mcs83_db;
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CREATE DATABASE mcs83_db;
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USE mcs83_db;
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CREATE TABLE t1 (t1_int INT, t1_char CHAR(5))ENGINE=Columnstore;
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CREATE TABLE t2 (t2_int INT, t2_char CHAR(5))ENGINE=Columnstore;
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INSERT INTO t1 VALUES (NULL, NULL),(1, 'aaa'),(2, 'bbb'),(3, 'ccc'),(4, 'ddd'),(5, 'aa'),(6, ''),(7, 'aaaaa');
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INSERT INTO t2 VALUES (NULL, NULL),(1, 'hhhh'),(3, 'iii'),(5, 'jjj'),(6, ''),(7, 'lll'),(9, 'm'),(11, 'nnn');
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SELECT * FROM t1 ORDER BY t1_int;
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t1_int t1_char
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NULL NULL
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1 aaa
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2 bbb
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3 ccc
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4 ddd
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5 aa
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6
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7 aaaaa
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SELECT * FROM t2 ORDER BY t2_int;
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t2_int t2_char
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NULL NULL
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1 hhhh
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3 iii
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5 jjj
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6
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7 lll
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9 m
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11 nnn
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DELETE t1 FROM t1 INNER JOIN t2 ON t1.t1_int=t2.t2_int AND t1.t1_char LIKE '%a%';
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SELECT * FROM t1 ORDER BY t1_int;
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t1_int t1_char
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NULL NULL
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2 bbb
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3 ccc
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4 ddd
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6
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DELETE t2 FROM t2 LEFT JOIN t1 ON t1.t1_int=t2.t2_int WHERE t2.t2_int IS NULL;
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SELECT * FROM t2 ORDER BY t2_int;
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t2_int t2_char
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1 hhhh
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3 iii
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5 jjj
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6
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7 lll
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9 m
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11 nnn
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DROP DATABASE mcs83_db;
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