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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.
		
			
				
	
	
		
			34 lines
		
	
	
		
			840 B
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
			
		
		
	
	
			34 lines
		
	
	
		
			840 B
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
#
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# Test MID() 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 mcs219_db;
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--enable_warnings
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CREATE DATABASE mcs219_db;
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USE mcs219_db;
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CREATE TABLE t1 (a INT, b CHAR(35))ENGINE=Columnstore;
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INSERT INTO t1 VALUES (NULL, NULL),(1, 'columnstore engine'),(2, 'mariadb database');
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SELECT b, MID(b,4,5) FROM t1;
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SELECT b, MID(b,12,5) FROM t1;
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SELECT b, MID(b,5,15) FROM t1;
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SELECT b, MID(b,12,15) FROM t1;
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SELECT b, MID(b,1,1) FROM t1;
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SELECT b, MID(b,1,2) FROM t1;
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SELECT b, MID(b,5,5) FROM t1;
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SELECT b, MID(b,-2,5) FROM t1;
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SELECT b, MID(b,-5,15) FROM t1;
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SELECT b, MID(b,-15,15) FROM t1;
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SELECT b, MID(b,0,0) FROM t1;
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SELECT b, MID(b,1,0) FROM t1;
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SELECT b, MID(b,0,1) FROM t1;
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SELECT b, MID(b,-1,0) FROM t1;
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# Clean UP
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DROP DATABASE mcs219_db;
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