42 lines
1.5 KiB
Plaintext
42 lines
1.5 KiB
Plaintext
drop table if exists t;
|
|
create table t (id int, c1 timestamp);
|
|
show columns from t;
|
|
Field Type Null Key Default Extra
|
|
id int(11) YES NULL
|
|
c1 timestamp YES NULL
|
|
explain t;
|
|
Field Type Null Key Default Extra
|
|
id int(11) YES NULL
|
|
c1 timestamp YES NULL
|
|
describe t;
|
|
Field Type Null Key Default Extra
|
|
id int(11) YES NULL
|
|
c1 timestamp YES NULL
|
|
desc t;
|
|
Field Type Null Key Default Extra
|
|
id int(11) YES NULL
|
|
c1 timestamp YES NULL
|
|
desc t c1;
|
|
Field Type Null Key Default Extra
|
|
c1 timestamp YES NULL
|
|
desc t id;
|
|
Field Type Null Key Default Extra
|
|
id int(11) YES NULL
|
|
drop table if exists t;
|
|
create table t(id int primary key, a int, b int);
|
|
set session tidb_hashagg_partial_concurrency = 1;
|
|
set session tidb_hashagg_final_concurrency = 1;
|
|
explain select group_concat(a) from t group by id;
|
|
id count task operator info
|
|
StreamAgg_8 8000.00 root group by:Column#6, funcs:group_concat(Column#5, ",")->Column#4
|
|
└─Projection_18 10000.00 root cast(test.t.a)->Column#5, test.t.id
|
|
└─TableReader_15 10000.00 root data:TableScan_14
|
|
└─TableScan_14 10000.00 cop[tikv] table:t, range:[-inf,+inf], keep order:true, stats:pseudo
|
|
explain select group_concat(a, b) from t group by id;
|
|
id count task operator info
|
|
StreamAgg_8 8000.00 root group by:Column#7, funcs:group_concat(Column#5, Column#6, ",")->Column#4
|
|
└─Projection_18 10000.00 root cast(test.t.a)->Column#5, cast(test.t.b)->Column#6, test.t.id
|
|
└─TableReader_15 10000.00 root data:TableScan_14
|
|
└─TableScan_14 10000.00 cop[tikv] table:t, range:[-inf,+inf], keep order:true, stats:pseudo
|
|
drop table t;
|