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1991a87d83
The Item_func_concat::val_str() function tries to make as less re-allocations as possible. This results in appending strings returned by 2nd and next arguments to the string returned by 1st argument if the buffer for the first argument has enough free space. A constant subselect is evaluated only once and its result is stored in an Item_cache_str. In the case when the first argument of the concat() function is such a subselect Item_cache_str returns the stored value and Item_func_concat::val_str() append values of other arguments to it. But for the next row the value in the Item_cache_str isn't restored because the subselect is a constant one and it isn't evaluated second time. This results in appending string values of 2nd and next arguments to the result of the previous Item_func_concat::val_str() call. The Item_func_concat::val_str() function now checks whether the first argument is a constant one and if so it doesn't append values of 2nd and next arguments to the string value returned by it. mysql-test/t/func_concat.test: Added test case for bug#16716: subselect in concat() may lead to a wrong result. mysql-test/r/func_concat.result: Added test case for bug#16716: subselect in concat() may lead to a wrong result. sql/item_strfunc.cc: Fixed bug#16716: subselect in concat() may lead to a wrong result. The Item_func_concat::val_str() function now checks whether the first argument is a constant one and if so it doesn't append values of 2nd and next arguments to the string value returned by it.
73 lines
1.9 KiB
Text
73 lines
1.9 KiB
Text
DROP TABLE IF EXISTS t1;
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CREATE TABLE t1 ( number INT NOT NULL, alpha CHAR(6) NOT NULL );
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INSERT INTO t1 VALUES (1413006,'idlfmv'),
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(1413065,'smpsfz'),(1413127,'sljrhx'),(1413304,'qerfnd');
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SELECT number, alpha, CONCAT_WS('<---->',number,alpha) AS new
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FROM t1 GROUP BY number;
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number alpha new
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1413006 idlfmv 1413006<---->idlfmv
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1413065 smpsfz 1413065<---->smpsfz
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1413127 sljrhx 1413127<---->sljrhx
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1413304 qerfnd 1413304<---->qerfnd
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SELECT CONCAT_WS('<---->',number,alpha) AS new
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FROM t1 GROUP BY new LIMIT 1;
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new
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1413006<---->idlfmv
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SELECT number, alpha, CONCAT_WS('<->',number,alpha) AS new
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FROM t1 GROUP BY new LIMIT 1;
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number alpha new
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1413006 idlfmv 1413006<->idlfmv
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SELECT number, alpha, CONCAT_WS('-',number,alpha,alpha,alpha,alpha,alpha,alpha,alpha) AS new
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FROM t1 GROUP BY new LIMIT 1;
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number alpha new
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1413006 idlfmv 1413006-idlfmv-idlfmv-idlfmv-idlfmv-idlfmv-idlfmv-idlfmv
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SELECT number, alpha, CONCAT_WS('<------------------>',number,alpha) AS new
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FROM t1 GROUP BY new LIMIT 1;
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number alpha new
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1413006 idlfmv 1413006<------------------>idlfmv
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drop table t1;
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create table t1 (a char(4), b double, c date, d tinyint(4));
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insert into t1 values ('AAAA', 105, '2003-03-01', 1);
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select * from t1 where concat(A,C,B,D) = 'AAAA2003-03-011051';
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a b c d
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AAAA 105 2003-03-01 1
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drop table t1;
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select 'a' union select concat('a', -4);
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a
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a
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a-4
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select 'a' union select concat('a', -4.5);
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a
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a
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a-4.5
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select 'a' union select concat('a', -(4 + 1));
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a
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a
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a-5
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select 'a' union select concat('a', 4 - 5);
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a
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a
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a-1
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select 'a' union select concat('a', -'3');
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a
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a
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a-3
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select 'a' union select concat('a', -concat('3',4));
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a
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a
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a-34
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select 'a' union select concat('a', -0);
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a
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a
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a0
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select 'a' union select concat('a', -0.0);
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a
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a
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good
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select concat((select x from (select 'a' as x) as t1 ),
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(select y from (select 'b' as y) as t2 )) from (select 1 union select 2 )
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as t3;
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concat((select x from (select 'a' as x) as t1 ),
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(select y from (select 'b' as y) as t2 ))
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ab
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ab
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