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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 estRows task access object operator info
StreamAgg_8 8000.00 root group by:Column#6, funcs:group_concat(Column#5 separator ",")->Column#4
└─Projection_18 10000.00 root cast(test.t.a, var_string(20))->Column#5, test.t.id
└─TableReader_15 10000.00 root data:TableFullScan_14
└─TableFullScan_14 10000.00 cop[tikv] table:t keep order:true, stats:pseudo
explain select group_concat(a, b) from t group by id;
id estRows task access object operator info
StreamAgg_8 8000.00 root group by:Column#7, funcs:group_concat(Column#5, Column#6 separator ",")->Column#4
└─Projection_18 10000.00 root cast(test.t.a, var_string(20))->Column#5, cast(test.t.b, var_string(20))->Column#6, test.t.id
└─TableReader_15 10000.00 root data:TableFullScan_14
└─TableFullScan_14 10000.00 cop[tikv] table:t keep order:true, stats:pseudo
drop table t;
drop view if exists v;
create view v as select cast(replace(substring_index(substring_index("",',',1),':',-1),'"','') as CHAR(32)) as event_id;
desc v;
Field Type Null Key Default Extra
event_id varchar(32) YES NULL