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When ordering by a column and partitioning by another, we must reset the peer_tracker for dense_rank, regardless if the value for the order column changes or not. Example: select a, b, dense_rank() over (partition by b order by a) a | b | dense_rank ---------------------- 1 | p1 | 1 2 | p1 | 2 2 | p2 | 1 // Here, without this fix we returned 0. 2 | p2 | 2 // And 1 here.
104 lines
1.9 KiB
Text
104 lines
1.9 KiB
Text
#
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# Try DENSE_RANK() function
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#
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create table t1 (
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pk int primary key,
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a int,
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b int
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);
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insert into t1 values
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( 1 , 0, 10),
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( 2 , 0, 10),
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( 3 , 1, 10),
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( 4 , 1, 10),
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( 8 , 2, 10),
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( 5 , 2, 20),
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( 6 , 2, 20),
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( 7 , 2, 20),
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( 9 , 4, 20),
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(10 , 4, 20);
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select pk, a, b, rank() over (order by a) as rank,
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dense_rank() over (order by a) as dense_rank
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from t1;
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pk a b rank dense_rank
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1 0 10 1 1
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2 0 10 1 1
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3 1 10 3 2
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4 1 10 3 2
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8 2 10 5 3
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5 2 20 5 3
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6 2 20 5 3
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7 2 20 5 3
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9 4 20 9 4
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10 4 20 9 4
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select pk, a, b, rank() over (partition by b order by a) as rank,
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dense_rank() over (partition by b order by a) as dense_rank
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from t1;
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pk a b rank dense_rank
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1 0 10 1 1
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2 0 10 1 1
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3 1 10 3 2
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4 1 10 3 2
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8 2 10 5 3
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5 2 20 1 1
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6 2 20 1 1
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7 2 20 1 1
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9 4 20 4 2
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10 4 20 4 2
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drop table t1;
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#
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# Test with null values in the table.
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#
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create table t2 (s1 int, s2 char(5));
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insert into t2 values (1,'a');
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insert into t2 values (null,null);
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insert into t2 values (1,null);
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insert into t2 values (null,'a');
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insert into t2 values (null,'c');
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insert into t2 values (2,'b');
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insert into t2 values (-1,'');
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select *, rank() over (order by s1) as rank,
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dense_rank() over (order by s1) as dense_rank
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from t2;
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s1 s2 rank dense_rank
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1 a 5 3
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NULL NULL 1 1
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1 NULL 5 3
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NULL a 1 1
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NULL c 1 1
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2 b 7 4
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-1 4 2
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select *, rank() over (partition by s2 order by s1) as rank,
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dense_rank() over (partition by s2 order by s1) as dense_rank
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from t2;
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s1 s2 rank dense_rank
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1 a 2 2
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NULL NULL 1 1
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1 NULL 2 2
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NULL a 1 1
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NULL c 1 1
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2 b 1 1
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-1 1 1
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select *, rank() over (order by s2) as rank,
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dense_rank() over (order by s2) as dense_rank
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from t2;
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s1 s2 rank dense_rank
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1 a 4 3
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NULL NULL 1 1
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1 NULL 1 1
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NULL a 4 3
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NULL c 7 5
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2 b 6 4
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-1 3 2
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select *, rank() over (partition by s1 order by s2) as rank,
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dense_rank() over (partition by s1 order by s2) as dense_rank
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from t2;
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s1 s2 rank dense_rank
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1 a 2 2
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NULL NULL 1 1
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1 NULL 1 1
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NULL a 2 2
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NULL c 3 3
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2 b 1 1
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-1 1 1
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drop table t2;
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