46 lines
2.6 KiB
Plaintext
46 lines
2.6 KiB
Plaintext
drop database if exists aggr_db;
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create database aggr_db;
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use aggr_db;
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create table t1(a int, b int);
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create table t2(a int, b int);
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create table t3(a int, b int);
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#聚集没有上推
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select (select count(t2.a) from t2) from t1;
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#没有上推
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select a, (select count(t2.a) from t2) from t1 group by b;
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#聚集上推
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select count((select count(t2.a) from t2)) from t1;
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--error 5176
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select count((select count(t1.a) from t2)) from t1;
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--error count(t1.a+(select count(t1.a) from t2)) from t1;
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#没有上推，聚集含有第二层的基础列
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select a as c, b from t1 having b>(select count(t2.a+c) from t2);
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#没有上推，聚集含有第二层的alias列
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select a as c, b from t1 having b>(select t1.a as d from t2 having count(d)>0);
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select a as c, b from t1 having b>(select t1.a as d from t2 having count(c)>0);
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select a from t1 having a=(select 1+t1.a as c from t2 order by(select count(t1.a) from t3));
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select a from t1 having a=(select 1+t1.a as c from t2 order by(select count(1+t1.a) from t3));
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select a from t1 having a=(select 1+t1.a as c from t2 order by(select count(t1.a+c) from t3));
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select a from t1 having a=(select 1+t1.a as c from t2 order by(select count(c) from t3));
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select a from t1 having a=(select 1+t1.a as c from t2 order by(select count(t1.a+c) from t3));
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select a from t1 having a=(select 1+t1.a as c from t2 order by(select count(t1.a+c) from t3));
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select a from t1 having a=(select 1+t1.a as c from t2 order by(select count(t1.a+t1.a) from t3));
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select a from t1 having a=(select 1+t2.a as c from t2 order by(select count(t1.a+c) from t3));
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#第二层的count()不能被提升到第一层
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--error 5176
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select a from t1 having a=(select 1+t1.a as c from t2 having count(t1.a+(select count(c) from t3))>0);
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select a from t1 having a=(select 1+t1.a as c from t2 having count(t1.a+(select 1+t1.a as cc from t3 having count(cc)>0))>0);
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select a from t1 where exists(select max(t1.a) from t2);
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SELECT t1.a FROM t1 GROUP BY t1.a HAVING t1.a < ALL(SELECT t2.a FROM t2 GROUP BY t2.a HAVING EXISTS(SELECT t3.a FROM t3 GROUP BY t3.a HAVING SUM(t1.a+t2.a) < t3.a/4));
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#子查询是union，union的左右支的aggr fun引用了上层查询的属性，该aggr func也不会上推到该层，
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#aggr function的上推不会穿过union
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select (select count(t1.b) from t2 union select 1 from t2 where 12 < 3) from t1 group by t1.a;
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select a from t1 having count(*) > (select 1);
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#聚集函数出现在join table的子查询中
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select * from t1 join t2 on t1.a=(select count(t2.a));
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select * from t1 join (t2, t3) on t1.a=(select count(t2.a));
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#聚集函数上推，聚集函数中的subquery跟着被上推
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select (select count((select t1.a from t2)) from t2) from t1;
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