130 lines
2.2 KiB
Plaintext
130 lines
2.2 KiB
Plaintext
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drop table if exists t1;
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create table t1(n1 int, n2 int, s char(20), vs varchar(20), t text);
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insert into t1 values (1,11, 'one','eleven', 'eleven'),
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(1,11, 'one','eleven', 'eleven'),
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(2,11, 'two','eleven', 'eleven'),
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(2,12, 'two','twevle', 'twelve'),
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(2,13, 'two','thirteen', 'foo'),
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(2,13, 'two','thirteen', 'foo'),
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(2,13, 'two','thirteen', 'bar'),
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(NULL,13, 'two','thirteen', 'bar'),
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(2,NULL, 'two','thirteen', 'bar'),
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(2,13, NULL,'thirteen', 'bar'),
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(2,13, 'two',NULL, 'bar'),
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(2,13, 'two','thirteen', NULL);
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select distinct n1 from t1;
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n1
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1
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2
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NULL
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select count(distinct n1) from t1;
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count(distinct n1)
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2
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select distinct n2 from t1;
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n2
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11
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12
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13
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NULL
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select count(distinct n2) from t1;
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count(distinct n2)
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3
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select distinct s from t1;
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s
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one
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two
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NULL
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select count(distinct s) from t1;
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count(distinct s)
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2
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select distinct vs from t1;
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vs
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eleven
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twevle
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thirteen
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NULL
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select count(distinct vs) from t1;
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count(distinct vs)
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3
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select distinct t from t1;
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t
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eleven
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twelve
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foo
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bar
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NULL
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select count(distinct t) from t1;
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count(distinct t)
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4
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select distinct n1,n2 from t1;
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n1 n2
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1 11
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2 11
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2 12
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2 13
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NULL 13
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2 NULL
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select count(distinct n1,n2) from t1;
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count(distinct n1,n2)
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4
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select distinct n1,s from t1;
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n1 s
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1 one
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2 two
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NULL two
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2 NULL
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select count(distinct n1,s) from t1;
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count(distinct n1,s)
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2
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select distinct s,n1,vs from t1;
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s n1 vs
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one 1 eleven
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two 2 eleven
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two 2 twevle
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two 2 thirteen
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two NULL thirteen
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NULL 2 thirteen
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two 2 NULL
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select count(distinct s,n1,vs) from t1;
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count(distinct s,n1,vs)
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4
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select distinct s,t from t1;
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s t
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one eleven
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two eleven
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two twelve
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two foo
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two bar
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NULL bar
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two NULL
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select count(distinct s,t) from t1;
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count(distinct s,t)
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5
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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(distinct n2), n1 from t1 group by n1;
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count(distinct n2) n1
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1 NULL
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1 1
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3 2
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drop table t1;
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create table t1 (n int default NULL);
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flush status;
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select count(distinct n) from t1;
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count(distinct n)
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5000
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show status like 'Created_tmp_disk_tables';
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Variable_name Value
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Created_tmp_disk_tables 0
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drop table t1;
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create table t1 (s text);
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flush status;
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select count(distinct s) from t1;
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count(distinct s)
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5000
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show status like 'Created_tmp_disk_tables';
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Variable_name Value
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Created_tmp_disk_tables 1
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drop table t1;
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