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94 lines
2.8 KiB
Text
94 lines
2.8 KiB
Text
select (select 2);
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(select 2)
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2
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drop table if exists t1,t2,t3,t4,attend,clinic;
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create table t1 (a int);
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create table t2 (a int, b int);
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create table t3 (a int);
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create table t4 (a int, b int);
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insert into t1 values (2);
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insert into t2 values (1,7),(2,7);
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insert into t4 values (4,8),(3,8),(5,9);
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select (select a from t1 where t1.a=t2.a), a from t2;
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(select a from t1 where t1.a=t2.a) a
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NULL 1
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2 2
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select (select a from t1 where t1.a=t2.b), a from t2;
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(select a from t1 where t1.a=t2.b) a
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NULL 1
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NULL 2
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select (select a from t1), a from t2;
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(select a from t1) a
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2 1
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2 2
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select (select a from t3), a from t2;
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(select a from t3) a
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NULL 1
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NULL 2
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select * from t2 where t2.a=(select a from t1);
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a b
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2 7
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insert into t3 values (6),(7),(3);
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select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1);
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a b
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1 7
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2 7
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select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1)
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union (select * from t4 order by a limit 2) limit 3;
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a b
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1 7
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2 7
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3 8
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select * from t2 where t2.b=(select a from t3 order by 1 desc limit 1)
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union (select * from t4 where t4.b=(select max(t2.a)*4 from t2) order by a);
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a b
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1 7
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2 7
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3 8
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4 8
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select (select a from t3 where a<t2.a*4 order by 1 desc limit 1), a from t2;
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(select a from t3 where a<t2.a*4 order by 1 desc limit 1) a
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3 1
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7 2
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select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
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(select * from t2 where a>1) as tt;
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(select t3.a from t3 where a<8 order by 1 desc limit 1) a
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7 2
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select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
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a
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2
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select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3 where t3.a > t1.a) order by 1 desc limit 1);
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a
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2
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select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3 where t3.a < t1.a) order by 1 desc limit 1);
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a
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select b,(select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2) from t4;
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b (select avg(t2.a+(select min(t3.a) from t3 where t3.a >= t4.a)) from t2)
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8 7.5000
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8 4.5000
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9 7.5000
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select * from t3 where exists (select * from t2 where t2.b=t3.a);
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a
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7
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select * from t3 where not exists (select * from t2 where t2.b=t3.a);
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a
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6
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3
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insert into t4 values (12,7),(1,7),(10,9),(9,6),(7,6),(3,9);
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select b,max(a) as ma from t4 group by b having b < (select max(t2.a)
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from t2 where t2.b=t4.b);
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b ma
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select b,max(a) as ma from t4 group by b having b >= (select max(t2.a)
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from t2 where t2.b=t4.b);
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b ma
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7 12
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create table attend (patient_uq int, clinic_uq int, index i1 (clinic_uq));
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create table clinic( uq int primary key, name char(25));
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insert into clinic values(1,"Oblastnaia bolnitsa"),(2,"Bolnitsa Krasnogo Kresta");
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insert into attend values (1,1),(1,2),(2,2),(1,3);
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select * from attend where exists (select * from clinic where uq = clinic_uq);
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patient_uq clinic_uq
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1 1
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1 2
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2 2
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drop table t1,t2,t3,t4,attend,clinic;
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