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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.
45 lines
983 B
Plaintext
45 lines
983 B
Plaintext
DROP DATABASE IF EXISTS mcs225_db;
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CREATE DATABASE mcs225_db;
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USE mcs225_db;
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CREATE TABLE t1 (a INT, b CHAR(20))ENGINE=Columnstore;
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INSERT INTO t1 VALUES (NULL, NULL),(1, 'aaa'),(2, 'abcabc'),(3, 'cccbba'),(4, 'dddd'),(5, 'pqrs');
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SELECT REPLACE('abbcccb', 'b', 'z');
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REPLACE('abbcccb', 'b', 'z')
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azzcccz
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SELECT REPLACE('xyz', 'z', 'ppp');
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REPLACE('xyz', 'z', 'ppp')
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xyppp
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SELECT b, REPLACE(b, 'a', 'mcs') FROM t1 ORDER BY 1;
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b REPLACE(b, 'a', 'mcs')
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NULL NULL
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aaa mcsmcsmcs
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abcabc mcsbcmcsbc
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cccbba cccbbmcs
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dddd dddd
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pqrs pqrs
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SELECT b, REPLACE(b, 'b', 'oo') FROM t1 ORDER BY 1;
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b REPLACE(b, 'b', 'oo')
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NULL NULL
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aaa aaa
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abcabc aoocaooc
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cccbba cccooooa
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dddd dddd
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pqrs pqrs
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SELECT b, REPLACE(b, 'pqrs', 'a') FROM t1 ORDER BY 1;
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b REPLACE(b, 'pqrs', 'a')
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NULL NULL
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aaa aaa
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abcabc abcabc
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cccbba cccbba
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dddd dddd
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pqrs a
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SELECT b, REPLACE(b, 'dd', 'n') FROM t1 ORDER BY 1;
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b REPLACE(b, 'dd', 'n')
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NULL NULL
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aaa aaa
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abcabc abcabc
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cccbba cccbba
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dddd nn
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pqrs pqrs
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DROP DATABASE mcs225_db;
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