set tidb_cost_model_version=1;
drop table if exists t;
create table t (id int, c1 timestamp);
show columns from t;
Field	Type	Null	Key	Default	Extra
id	int	YES		NULL	
c1	timestamp	YES		NULL	
explain t;
Field	Type	Null	Key	Default	Extra
id	int	YES		NULL	
c1	timestamp	YES		NULL	
describe t;
Field	Type	Null	Key	Default	Extra
id	int	YES		NULL	
c1	timestamp	YES		NULL	
desc t;
Field	Type	Null	Key	Default	Extra
id	int	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	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 format = 'brief' select group_concat(a) from t group by id;
id	estRows	task	access object	operator info
StreamAgg	8000.00	root		group by:Column#6, funcs:group_concat(Column#5 separator ",")->Column#4
└─Projection	10000.00	root		cast(explain.t.a, var_string(20))->Column#5, explain.t.id->Column#6
  └─TableReader	10000.00	root		data:TableFullScan
    └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:true, stats:pseudo
explain format = 'brief' select group_concat(a, b) from t group by id;
id	estRows	task	access object	operator info
StreamAgg	8000.00	root		group by:Column#7, funcs:group_concat(Column#5, Column#6 separator ",")->Column#4
└─Projection	10000.00	root		cast(explain.t.a, var_string(20))->Column#5, cast(explain.t.b, var_string(20))->Column#6, explain.t.id->Column#7
  └─TableReader	10000.00	root		data:TableFullScan
    └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:true, stats:pseudo
explain format = TRADITIONAL 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(explain.t.a, var_string(20))->Column#5, cast(explain.t.b, var_string(20))->Column#6, explain.t.id->Column#7
  └─TableReader_15	10000.00	root		data:TableFullScan_14
    └─TableFullScan_14	10000.00	cop[tikv]	table:t	keep order:true, stats:pseudo
explain format = 'row' 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(explain.t.a, var_string(20))->Column#5, cast(explain.t.b, var_string(20))->Column#6, explain.t.id->Column#7
  └─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)	NO		NULL