github.com/matrixorigin/matrixone@v1.2.0/test/distributed/cases/optimizer/union.result (about)

     1  drop database if exists d1;
     2  create database d1;
     3  use d1;
     4  drop table if exists t1;
     5  drop table if exists t2;
     6  create table t1(c1 int primary key, c2 int, c3 int);
     7  create table t2(c1 int, c2 int, c3 int, primary key(c1,c2));
     8  explain select * from t1 union select * from t2;
     9  QUERY PLAN
    10  Project
    11    ->  Union
    12          ->  Project
    13                ->  Table Scan on d1.t1
    14          ->  Project
    15                ->  Table Scan on d1.t2
    16  explain select * from t1 union select * from t1;
    17  QUERY PLAN
    18  Project
    19    ->  Table Scan on d1.t1
    20  explain select * from t2 union select * from t2;
    21  QUERY PLAN
    22  Project
    23    ->  Table Scan on d1.t2
    24  explain select c1 from t1 group by c1;
    25  QUERY PLAN
    26  Project
    27    ->  Table Scan on d1.t1
    28  explain select c1 from t2 group by c1;
    29  QUERY PLAN
    30  Project
    31    ->  Aggregate
    32          Group Key: t2.c1
    33          ->  Table Scan on d1.t2
    34  explain select c1,c2 from t2 group by c1,c2;
    35  QUERY PLAN
    36  Project
    37    ->  Table Scan on d1.t2
    38  drop database if exists d1;