oceanbase

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drop table if exists t1;
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create table t1 (id int primary key, n1 int, n2 int, s varchar(20), vs varchar(20), t varchar(256));
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insert into t1 values (0, NULL, NULL, 'zero', 'zero', 'zero'), (1,1,11, 'one','eleven', 'eleven'),  (2,1,11, 'one','eleven', 'eleven'),  (3,2,11, 'two','eleven', 'eleven'),  (4,2,12, 'two','twevle', 'twelve'),  (5,2,13, 'two','thirteen', 'foo'),  (6,2,13, 'two','thirteen', 'foo'),  (7,2,13, 'two','thirteen', 'bar'),  (8,NULL,13, 'two','thirteen', 'bar'),  (9,2,NULL, 'two','thirteen', 'bar'),  (10,2,13, NULL,'thirteen', 'bar'),  (11,2,13, 'two',NULL, 'bar'),  (12,2,13, 'two','thirteen', NULL);
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select n1, n2 from t1;
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n1	n2
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NULL	NULL
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1	11
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1	11
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2	11
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2	12
11
2	13
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2	13
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2	13
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NULL	13
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2	NULL
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2	13
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2	13
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2	13
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select count(distinct n1), count(distinct n2) from t1;
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count(distinct n1)	count(distinct n2)
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2	3
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select count(n1), count(distinct n1), count(n2), count(distinct n2) from t1;
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count(n1)	count(distinct n1)	count(n2)	count(distinct n2)
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11	2	11	3
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select count(distinct n1), count(distinct n2), count(n1), count(n2) from t1;
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count(distinct n1)	count(distinct n2)	count(n1)	count(n2)
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2	3	11	11
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