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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.
24 lines
635 B
Plaintext
24 lines
635 B
Plaintext
#
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# Test MAX as distributed aggregate function
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# Author: Bharath, bharath.bokka@mariadb.com
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#
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-- source ../include/have_columnstore.inc
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--disable_warnings
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DROP DATABASE IF EXISTS mcs190_db;
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--enable_warnings
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CREATE DATABASE mcs190_db;
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USE mcs190_db;
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CREATE TABLE t1 (a INT, b CHAR(5))ENGINE=Columnstore;
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INSERT INTO t1 VALUES (NULL, NULL),(1, 'aaa'),(2, 'aaa'),(1, 'ccc'),(4, 'ddd'),(5, 'aaa'),(6, 'ddd'),(7, 'eee');
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SELECT MAX(DISTINCT a) FROM t1;
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SELECT MAX(DISTINCT a) FROM t1 GROUP BY b HAVING b = 'aaa';
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SELECT b, MAX(DISTINCT a) FROM t1 GROUP BY b ORDER BY b DESC;
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SELECT MAX(a) FROM t1;
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# Clean UP
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DROP DATABASE mcs190_db;
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