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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.
46 lines
1.0 KiB
Plaintext
46 lines
1.0 KiB
Plaintext
DROP DATABASE IF EXISTS mcs285_db;
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CREATE DATABASE mcs285_db;
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USE mcs285_db;
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CREATE TABLE t1 (a INT, b CHAR(15))ENGINE=Columnstore;
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INSERT INTO t1 VALUES (NULL, NULL),(1, 'mariadb'),(2, 'columnstore'),(3, 'Innodb');
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SELECT RIGHT('mariadb cs', 2) FROM t1 LIMIT 1;
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RIGHT('mariadb cs', 2)
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cs
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SELECT RIGHT('mariadb cs', 3) FROM t1 LIMIT 1;
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RIGHT('mariadb cs', 3)
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cs
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SELECT RIGHT('mariadb cs', 4) FROM t1 LIMIT 1;
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RIGHT('mariadb cs', 4)
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b cs
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SELECT b, RIGHT(b, 0) FROM t1 ORDER BY 1;
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b RIGHT(b, 0)
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NULL NULL
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columnstore
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Innodb
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mariadb
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SELECT b, RIGHT(b, -1) FROM t1 ORDER BY 1;
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b RIGHT(b, -1)
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NULL NULL
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columnstore
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Innodb
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mariadb
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SELECT b, RIGHT(b, 6) FROM t1 ORDER BY 1;
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b RIGHT(b, 6)
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NULL NULL
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columnstore nstore
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Innodb Innodb
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mariadb ariadb
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SELECT b, RIGHT(b, 9) FROM t1 ORDER BY 1;
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b RIGHT(b, 9)
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NULL NULL
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columnstore lumnstore
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Innodb Innodb
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mariadb mariadb
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SELECT b, RIGHT(concat(b, '_mmm'), 10) FROM t1 ORDER BY 1;
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b RIGHT(concat(b, '_mmm'), 10)
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NULL NULL
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columnstore nstore_mmm
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Innodb Innodb_mmm
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mariadb ariadb_mmm
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DROP DATABASE mcs285_db;
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