DROP TABLE IF EXISTS t;
CREATE TABLE t (
c1 int,
c2 int,
c3 int,
PRIMARY KEY (c1)
);
INSERT INTO t VALUES (1,2,3);
set session tidb_hashagg_partial_concurrency = 1;
set session tidb_hashagg_final_concurrency = 1;
SELECT * from t;
c1	c2	c3
1	2	3
SELECT c1, c2, c3 from t;
c1	c2	c3
1	2	3
SELECT c1, c1 from t;
c1	c1
1	1
SELECT c1 as a, c2 as a from t;
a	a
1	2
SELECT 1;
1
1
SELECT 1, 1;
1	1
1	1
SET @@autocommit = 1;
SELECT @@autocommit;
@@autocommit
1
SELECT @@autocommit, @@autocommit;
@@autocommit	@@autocommit
1	1
SET @a = 10;
SET @b = 11;
SELECT @a, @@autocommit;
@a	@@autocommit
10	1
SELECT @a, @b;
@a	@b
10	11
SELECT 1, @a;
1	@a
1	10
SELECT 1, @a as a;
1	a
1	10
SELECT 1, @a, @@autocommit as a, c1 from t;
1	@a	a	c1
1	10	1	1
SET @b = "123";
SELECT @b + "123";
@b + "123"
246
SELECT 1 + 1;
1 + 1
2
SELECT 1 a, 1 as a, 1 + 1 a;
a	a	a
1	1	2
SELECT c1 a, c1 as a from t;
a	a
1	1
SELECT * from t LIMIT 0,1;
c1	c2	c3
1	2	3
SELECT * from t LIMIT 1;
c1	c2	c3
1	2	3
SELECT * from t LIMIT 1,1;
c1	c2	c3
SELECT * from t LIMIT 1 OFFSET 0;
c1	c2	c3
1	2	3
DROP TABLE IF EXISTS t2;
CREATE TABLE t2 (
c1 int,
c2 int,
PRIMARY KEY (c1)
);
INSERT INTO t2 VALUES (1,2);
SELECT * from t a;
c1	c2	c3
1	2	3
SELECT * from t a, t2 b;
c1	c2	c3	c1	c2
1	2	3	1	2
SELECT * from t as a, t2 as b;
c1	c2	c3	c1	c2
1	2	3	1	2
SELECT * from t a left join t2 b on a.c1 = b.c1;
c1	c2	c3	c1	c2
1	2	3	1	2
SELECT * from (SELECT 1, 1) as a;
Error 1060: Duplicate column name '1'
SELECT * from (SELECT * FROM t, t2) as a;
Error 1060: Duplicate column name 'c1'
DROP TABLE IF EXISTS t;
CREATE TABLE t (c1 INT, c2 INT);
INSERT INTO t VALUES (1, 2), (1, 1), (1, 3);
SELECT c1=c2 FROM t;
c1=c2
0
1
0
SELECT 1=1;
1=1
1
SELECT t.c1 + t.c2 from t limit 1;
t.c1 + t.c2
3
SELECT t.c1 from t limit 1;
c1
1
SELECT t.c1 + c2 from t limit 1;
t.c1 + c2
3
SELECT c1 + 10 from t limit 1;
c1 + 10
11
SELECT t.c1 + 10 from t limit 1;
t.c1 + 10
11
SELECT all c1, c2 from t limit 1;
c1	c2
1	2
SELECT distinct c1, c2 from t order by c1, c2 limit 1;
c1	c2
1	1
SELECT c2 from t where not (c2 > 2);
c2
2
1
select c2 from t where not null is null;
c2
select !(1 + 2);
!(1 + 2)
0
select + - 1, --1, +-+-+1, + "123";
+ - 1	--1	+-+-+1	123
-1	1	1	123
select --------------------1, ++++++++++++++++++++1;
--------------------1	1
1	1
select +(+(1)), (-+1), ((+1)), +1.23, +1e23, +1E23, +null, +true, +false, + ( ( 1 ) );
1	(-+1)	1	1.23	1e23	1E23	NULL	TRUE	FALSE	1
1	-1	1	1.23	1e23	1e23	NULL	1	0	1
select +
(
+
(
1
)
)
;
1
1
select +	(	+	1	);
1
1
select --+(1 + 1), +-+-(1 * 1);
--+(1 + 1)	+-+-(1 * 1)
2	1
select * from t where null;
c1	c2
select * from t where 1;
c1	c2
1	2
1	1
1	3
select * from t where 0;
c1	c2
select * from t where 0 * 10;
c1	c2
select * from t where null is not null;
c1	c2
select * from t where !1;
c1	c2
select * from t where 1 && 0 || 3 && null;
c1	c2
select * from t as a, t2 as b;
c1	c2	c1	c2
1	2	1	2
1	1	1	2
1	3	1	2
select * from t as a cross join t2 as b;
c1	c2	c1	c2
1	2	1	2
1	1	1	2
1	3	1	2
select * from t as a join t2 as b;
c1	c2	c1	c2
1	2	1	2
1	1	1	2
1	3	1	2
select * from t as a join t2 as b on a.c2 = b.c2;
c1	c2	c1	c2
1	2	1	2
select * from (t);
c1	c2
1	2
1	1
1	3
select * from (t as a, t2 as b);
c1	c2	c1	c2
1	2	1	2
1	1	1	2
1	3	1	2
select * from (t as a cross join t2 as b);
c1	c2	c1	c2
1	2	1	2
1	1	1	2
1	3	1	2
select 1 as a from t;
a
1
1
1
select count(*), 1 from t;
count(*)	1
3	1
select *, 1 from t;
c1	c2	1
1	2	1
1	1	1
1	3	1
select 1, count(1), sum(1);
1	count(1)	sum(1)
1	1	1
drop table if exists t1;
create table t1(a int primary key, b int, c int, index idx(b, c));
insert into t1 values(1, 2, 3);
insert into t1 values(2, 3, 4);
insert into t1 values(3 ,4, 5);
insert into t1 values(4, 5, 6);
insert into t1 values(5, 6, 7);
insert into t1 values(6, 7, 8);
insert into t1 values(7, 8, 9);
insert into t1 values(9, 10, 11);
explain format = 'brief' select a, c from t1 use index(idx) order by a limit 5;
id	estRows	task	access object	operator info
TopN	5.00	root		test.t1.a, offset:0, count:5
└─IndexReader	5.00	root		index:TopN
  └─TopN	5.00	cop[tikv]		test.t1.a, offset:0, count:5
    └─IndexFullScan	10000.00	cop[tikv]	table:t1, index:idx(b, c)	keep order:false, stats:pseudo
select c, a from t1 use index(idx) order by a limit 5;
c	a
3	1
4	2
5	3
6	4
7	5
drop table if exists t;
create table t (a int, b int, c int, key idx(a, b, c));
explain format = 'brief' select count(a) from t;
id	estRows	task	access object	operator info
StreamAgg	1.00	root		funcs:count(Column#13)->Column#5
└─TableReader	1.00	root		data:StreamAgg
  └─StreamAgg	1.00	cop[tikv]		funcs:count(test.t.a)->Column#13
    └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
select count(a) from t;
count(a)
0
insert t values(0,0,0);
explain format = 'brief' select distinct b from t group by a;
id	estRows	task	access object	operator info
HashAgg	8000.00	root		group by:test.t.b, funcs:firstrow(test.t.b)->test.t.b
└─StreamAgg	8000.00	root		group by:test.t.a, funcs:firstrow(Column#9)->test.t.b
  └─IndexReader	8000.00	root		index:StreamAgg
    └─StreamAgg	8000.00	cop[tikv]		group by:test.t.a, funcs:firstrow(test.t.b)->Column#9
      └─IndexFullScan	10000.00	cop[tikv]	table:t, index:idx(a, b, c)	keep order:true, stats:pseudo
select distinct b from t group by a;
b
0
explain format = 'brief' select count(b) from t group by a;
id	estRows	task	access object	operator info
StreamAgg	8000.00	root		group by:test.t.a, funcs:count(Column#10)->Column#5
└─IndexReader	8000.00	root		index:StreamAgg
  └─StreamAgg	8000.00	cop[tikv]		group by:test.t.a, funcs:count(test.t.b)->Column#10
    └─IndexFullScan	10000.00	cop[tikv]	table:t, index:idx(a, b, c)	keep order:true, stats:pseudo
select count(b) from t group by a;
count(b)
1
insert t values(1,1,1),(3,3,6),(3,2,5),(2,1,4),(1,1,3),(1,1,2);
explain format = 'brief' select count(a) from t where b>0 group by a, b;
id	estRows	task	access object	operator info
StreamAgg	2666.67	root		group by:test.t.a, test.t.b, funcs:count(Column#10)->Column#5
└─IndexReader	2666.67	root		index:StreamAgg
  └─StreamAgg	2666.67	cop[tikv]		group by:test.t.a, test.t.b, funcs:count(test.t.a)->Column#10
    └─Selection	3333.33	cop[tikv]		gt(test.t.b, 0)
      └─IndexFullScan	10000.00	cop[tikv]	table:t, index:idx(a, b, c)	keep order:true, stats:pseudo
select count(a) from t where b>0 group by a, b;
count(a)
3
1
1
1
explain format = 'brief' select count(a) from t where b>0 group by a, b order by a;
id	estRows	task	access object	operator info
Projection	2666.67	root		Column#5
└─StreamAgg	2666.67	root		group by:test.t.a, test.t.b, funcs:count(Column#15)->Column#5, funcs:firstrow(test.t.a)->test.t.a
  └─IndexReader	2666.67	root		index:StreamAgg
    └─StreamAgg	2666.67	cop[tikv]		group by:test.t.a, test.t.b, funcs:count(test.t.a)->Column#15
      └─Selection	3333.33	cop[tikv]		gt(test.t.b, 0)
        └─IndexFullScan	10000.00	cop[tikv]	table:t, index:idx(a, b, c)	keep order:true, stats:pseudo
select count(a) from t where b>0 group by a, b order by a;
count(a)
3
1
1
1
explain format = 'brief' select count(a) from t where b>0 group by a, b order by a limit 1;
id	estRows	task	access object	operator info
Projection	1.00	root		Column#5
└─Limit	1.00	root		offset:0, count:1
  └─StreamAgg	1.00	root		group by:test.t.a, test.t.b, funcs:count(Column#16)->Column#5, funcs:firstrow(test.t.a)->test.t.a
    └─IndexReader	1.00	root		index:StreamAgg
      └─StreamAgg	1.00	cop[tikv]		group by:test.t.a, test.t.b, funcs:count(test.t.a)->Column#16
        └─Selection	1.25	cop[tikv]		gt(test.t.b, 0)
          └─IndexFullScan	3.75	cop[tikv]	table:t, index:idx(a, b, c)	keep order:true, stats:pseudo
select count(a) from t where b>0 group by a, b order by a limit 1;
count(a)
3
drop table if exists t;
create table t (id int primary key, a int, b int);
explain format = 'brief' select * from (t t1 left join t t2 on t1.a = t2.a) left join (t t3 left join t t4 on t3.a = t4.a) on t2.b = 1;
id	estRows	task	access object	operator info
HashJoin	155937656.25	root		CARTESIAN left outer join, left cond:[eq(test.t.b, 1)]
├─HashJoin(Build)	12487.50	root		left outer join, equal:[eq(test.t.a, test.t.a)]
│ ├─TableReader(Build)	9990.00	root		data:Selection
│ │ └─Selection	9990.00	cop[tikv]		not(isnull(test.t.a))
│ │   └─TableFullScan	10000.00	cop[tikv]	table:t4	keep order:false, stats:pseudo
│ └─TableReader(Probe)	10000.00	root		data:TableFullScan
│   └─TableFullScan	10000.00	cop[tikv]	table:t3	keep order:false, stats:pseudo
└─HashJoin(Probe)	12487.50	root		left outer join, equal:[eq(test.t.a, test.t.a)]
  ├─TableReader(Build)	9990.00	root		data:Selection
  │ └─Selection	9990.00	cop[tikv]		not(isnull(test.t.a))
  │   └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
  └─TableReader(Probe)	10000.00	root		data:TableFullScan
    └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo
drop table if exists t;
create table t(a bigint primary key, b bigint);
desc select * from t where a = 1;
id	estRows	task	access object	operator info
Point_Get_1	1.00	root	table:t	handle:1
desc select * from t where a = '1';
id	estRows	task	access object	operator info
Point_Get_1	1.00	root	table:t	handle:1
desc select sysdate(), sleep(1), sysdate();
id	estRows	task	access object	operator info
Projection_3	1.00	root		sysdate()->Column#1, sleep(1)->Column#2, sysdate()->Column#3
└─TableDual_4	1.00	root		rows:1
drop table if exists th;
set @@session.tidb_enable_table_partition = '1';
set @@session.tidb_partition_prune_mode = 'static';
create table th (a int, b int) partition by hash(a) partitions 3;
insert into th values (0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8);
insert into th values (-1,-1),(-2,-2),(-3,-3),(-4,-4),(-5,-5),(-6,-6),(-7,-7),(-8,-8);
desc select * from th where a=-2;
id	estRows	task	access object	operator info
TableReader_9	10.00	root		data:Selection_8
└─Selection_8	10.00	cop[tikv]		eq(test.th.a, -2)
  └─TableFullScan_7	10000.00	cop[tikv]	table:th, partition:p2	keep order:false, stats:pseudo
desc select * from th;
id	estRows	task	access object	operator info
PartitionUnion_9	30000.00	root		
├─TableReader_11	10000.00	root		data:TableFullScan_10
│ └─TableFullScan_10	10000.00	cop[tikv]	table:th, partition:p0	keep order:false, stats:pseudo
├─TableReader_13	10000.00	root		data:TableFullScan_12
│ └─TableFullScan_12	10000.00	cop[tikv]	table:th, partition:p1	keep order:false, stats:pseudo
└─TableReader_15	10000.00	root		data:TableFullScan_14
  └─TableFullScan_14	10000.00	cop[tikv]	table:th, partition:p2	keep order:false, stats:pseudo
desc select * from th partition (p2,p1);
id	estRows	task	access object	operator info
PartitionUnion_8	20000.00	root		
├─TableReader_10	10000.00	root		data:TableFullScan_9
│ └─TableFullScan_9	10000.00	cop[tikv]	table:th, partition:p1	keep order:false, stats:pseudo
└─TableReader_12	10000.00	root		data:TableFullScan_11
  └─TableFullScan_11	10000.00	cop[tikv]	table:th, partition:p2	keep order:false, stats:pseudo
set @@session.tidb_partition_prune_mode = 'dynamic';
desc select * from th where a=-2;
id	estRows	task	access object	operator info
TableReader_7	10.00	root	partition:p2	data:Selection_6
└─Selection_6	10.00	cop[tikv]		eq(test.th.a, -2)
  └─TableFullScan_5	10000.00	cop[tikv]	table:th	keep order:false, stats:pseudo
desc select * from th;
id	estRows	task	access object	operator info
TableReader_5	10000.00	root	partition:all	data:TableFullScan_4
└─TableFullScan_4	10000.00	cop[tikv]	table:th	keep order:false, stats:pseudo
desc select * from th partition (p2,p1);
id	estRows	task	access object	operator info
TableReader_5	10000.00	root	partition:p1,p2	data:TableFullScan_4
└─TableFullScan_4	10000.00	cop[tikv]	table:th	keep order:false, stats:pseudo
set @@session.tidb_partition_prune_mode = DEFAULT;
drop table if exists t;
create table t(a int, b int);
explain format = 'brief' select a != any (select a from t t2) from t t1;
id	estRows	task	access object	operator info
Projection	10000.00	root		and(or(or(gt(Column#11, 1), ne(test.t.a, Column#10)), if(ne(Column#12, 0), <nil>, 0)), and(ne(Column#13, 0), if(isnull(test.t.a), <nil>, 1)))->Column#14
└─HashJoin	10000.00	root		CARTESIAN inner join
  ├─StreamAgg(Build)	1.00	root		funcs:max(Column#16)->Column#10, funcs:count(distinct Column#17)->Column#11, funcs:sum(Column#18)->Column#12, funcs:count(1)->Column#13
  │ └─Projection	10000.00	root		test.t.a, test.t.a, cast(isnull(test.t.a), decimal(20,0) BINARY)->Column#18
  │   └─TableReader	10000.00	root		data:TableFullScan
  │     └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
  └─TableReader(Probe)	10000.00	root		data:TableFullScan
    └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo
explain format = 'brief' select a = all (select a from t t2) from t t1;
id	estRows	task	access object	operator info
Projection	10000.00	root		or(and(and(le(Column#11, 1), eq(test.t.a, Column#10)), if(ne(Column#12, 0), <nil>, 1)), or(eq(Column#13, 0), if(isnull(test.t.a), <nil>, 0)))->Column#14
└─HashJoin	10000.00	root		CARTESIAN inner join
  ├─StreamAgg(Build)	1.00	root		funcs:firstrow(Column#16)->Column#10, funcs:count(distinct Column#17)->Column#11, funcs:sum(Column#18)->Column#12, funcs:count(1)->Column#13
  │ └─Projection	10000.00	root		test.t.a, test.t.a, cast(isnull(test.t.a), decimal(20,0) BINARY)->Column#18
  │   └─TableReader	10000.00	root		data:TableFullScan
  │     └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
  └─TableReader(Probe)	10000.00	root		data:TableFullScan
    └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo
drop table if exists t;
create table t(a int, b int);
drop table if exists s;
create table s(a varchar(20), b varchar(20));
explain format = 'brief' select a in (select a from s where s.b = t.b) from t;
id	estRows	task	access object	operator info
HashJoin	10000.00	root		left outer semi join, equal:[eq(Column#11, Column#12)], other cond:eq(cast(test.t.a, double BINARY), cast(test.s.a, double BINARY))
├─Projection(Build)	10000.00	root		test.s.a, cast(test.s.b, double BINARY)->Column#12
│ └─TableReader	10000.00	root		data:TableFullScan
│   └─TableFullScan	10000.00	cop[tikv]	table:s	keep order:false, stats:pseudo
└─Projection(Probe)	10000.00	root		test.t.a, cast(test.t.b, double BINARY)->Column#11
  └─TableReader	10000.00	root		data:TableFullScan
    └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
explain format = 'brief' select a in (select a+b from t t2 where t2.b = t1.b) from t t1;
id	estRows	task	access object	operator info
HashJoin	10000.00	root		left outer semi join, equal:[eq(test.t.b, test.t.b)], other cond:eq(test.t.a, plus(test.t.a, test.t.b))
├─TableReader(Build)	10000.00	root		data:TableFullScan
│ └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
└─TableReader(Probe)	10000.00	root		data:TableFullScan
  └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo
drop table t;
create table t(a int not null, b int);
explain format = 'brief' select a in (select a from t t2 where t2.b = t1.b) from t t1;
id	estRows	task	access object	operator info
HashJoin	10000.00	root		left outer semi join, equal:[eq(test.t.b, test.t.b) eq(test.t.a, test.t.a)]
├─TableReader(Build)	10000.00	root		data:TableFullScan
│ └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
└─TableReader(Probe)	10000.00	root		data:TableFullScan
  └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo
explain format = 'brief' select 1 from (select sleep(1)) t;
id	estRows	task	access object	operator info
Projection	1.00	root		1->Column#2
└─Projection	1.00	root		sleep(1)->Column#1
  └─TableDual	1.00	root		rows:1
drop table if exists t;
create table t(a int, b int);
explain format = 'brief' select a from t order by rand();
id	estRows	task	access object	operator info
Projection	10000.00	root		test.t.a
└─Sort	10000.00	root		Column#4
  └─Projection	10000.00	root		test.t.a, rand()->Column#4
    └─TableReader	10000.00	root		data:TableFullScan
      └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
explain format = 'brief' select a, b from t order by abs(2);
id	estRows	task	access object	operator info
TableReader	10000.00	root		data:TableFullScan
└─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
explain format = 'brief' select a from t order by abs(rand())+1;
id	estRows	task	access object	operator info
Projection	10000.00	root		test.t.a
└─Sort	10000.00	root		Column#4
  └─Projection	10000.00	root		test.t.a, plus(abs(rand()), 1)->Column#4
    └─TableReader	10000.00	root		data:TableFullScan
      └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
drop table if exists t1;
create table t1(a int, b int);
drop table if exists t2;
create table t2(a int, b int);
explain format = 'brief' select * from t1 where t1.a in (select t2.a as a from t2 where t2.b > t1.b order by t1.b);
id	estRows	task	access object	operator info
HashJoin	7984.01	root		semi join, equal:[eq(test.t1.a, test.t2.a)], other cond:gt(test.t2.b, test.t1.b)
├─TableReader(Build)	9980.01	root		data:Selection
│ └─Selection	9980.01	cop[tikv]		not(isnull(test.t2.a)), not(isnull(test.t2.b))
│   └─TableFullScan	10000.00	cop[tikv]	table:t2	keep order:false, stats:pseudo
└─TableReader(Probe)	9980.01	root		data:Selection
  └─Selection	9980.01	cop[tikv]		not(isnull(test.t1.a)), not(isnull(test.t1.b))
    └─TableFullScan	10000.00	cop[tikv]	table:t1	keep order:false, stats:pseudo
drop table t;
CREATE TABLE t (id int(10) unsigned NOT NULL AUTO_INCREMENT,
i int(10) unsigned DEFAULT NULL,
x int(10) unsigned DEFAULT '0',
PRIMARY KEY (`id`)
);
explain format = 'brief' select row_number() over( partition by i ) - x as rnk from t;
id	estRows	task	access object	operator info
Projection	10000.00	root		minus(Column#5, test.t.x)->Column#7
└─Window	10000.00	root		row_number()->Column#5 over(partition by test.t.i rows between current row and current row)
  └─Sort	10000.00	root		test.t.i
    └─TableReader	10000.00	root		data:TableFullScan
      └─TableFullScan	10000.00	cop[tikv]	table:t	keep order:false, stats:pseudo
create table precise_types (
a BIGINT UNSIGNED NOT NULL,
b BIGINT NOT NULL,
c DECIMAL(21,1) NOT NULL,
d DOUBLE(21,1) NOT NULL
);
insert into precise_types values (
18446744073709551614,
-9223372036854775806,
99999999999999999999,
18446744073709551614
);
SELECT a, b, c, d FROM precise_types;
a	b	c	d
18446744073709551614	-9223372036854775806	99999999999999999999.0	1.8446744073709552e19
drop table if exists t1;
create table t1(a int, b int);
insert into t1 values (1,1),(2,2),(1,3),(2,3);
drop table if exists t2;
create table t2(a int, b int);
insert into t2 values (1,1),(2,2),(3,4);
drop table if exists t3;
create table t3(a int, b int);
insert into t3 values (1,1),(2,3);
drop table if exists t4;
create table t4(a int, b int);
analyze table t1,t2,t3;
explain format = 'brief' select * from t2 left join t1 on t2.a=t1.a left join t3 on t2.a=t3.a;
id	estRows	task	access object	operator info
Projection	4.00	root		test.t2.a, test.t2.b, test.t1.a, test.t1.b, test.t3.a, test.t3.b
└─HashJoin	4.00	root		left outer join, equal:[eq(test.t2.a, test.t1.a)]
  ├─TableReader(Build)	4.00	root		data:Selection
  │ └─Selection	4.00	cop[tikv]		not(isnull(test.t1.a))
  │   └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
  └─HashJoin(Probe)	3.00	root		left outer join, equal:[eq(test.t2.a, test.t3.a)]
    ├─TableReader(Build)	2.00	root		data:Selection
    │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.a))
    │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
    └─TableReader(Probe)	3.00	root		data:TableFullScan
      └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
explain format = 'brief' select * from t2 left join (t1 left join t3 on t1.a=t3.a) on t2.a=1;
id	estRows	task	access object	operator info
HashJoin	12.00	root		CARTESIAN left outer join, left cond:[eq(test.t2.a, 1)]
├─HashJoin(Build)	4.00	root		left outer join, equal:[eq(test.t1.a, test.t3.a)]
│ ├─TableReader(Build)	2.00	root		data:Selection
│ │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.a))
│ │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
│ └─TableReader(Probe)	4.00	root		data:TableFullScan
│   └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
└─TableReader(Probe)	3.00	root		data:TableFullScan
  └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
explain format = 'brief' select * from t2 left join (t1 left join t3 on t1.a=t3.a) on t2.a=t3.a;
id	estRows	task	access object	operator info
HashJoin	4.00	root		left outer join, equal:[eq(test.t2.a, test.t3.a)]
├─Projection(Build)	4.00	root		test.t1.a, test.t1.b, test.t3.a, test.t3.b
│ └─HashJoin	4.00	root		inner join, equal:[eq(test.t3.a, test.t1.a)]
│   ├─TableReader(Build)	2.00	root		data:Selection
│   │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.a))
│   │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
│   └─TableReader(Probe)	4.00	root		data:Selection
│     └─Selection	4.00	cop[tikv]		not(isnull(test.t1.a))
│       └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
└─TableReader(Probe)	3.00	root		data:TableFullScan
  └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
explain format = 'brief' select * from t2 left join t1 on t1.a=t2.a join t3 on t2.b=t3.b;
id	estRows	task	access object	operator info
Projection	4.00	root		test.t2.a, test.t2.b, test.t1.a, test.t1.b, test.t3.a, test.t3.b
└─HashJoin	4.00	root		left outer join, equal:[eq(test.t2.a, test.t1.a)]
  ├─HashJoin(Build)	2.00	root		inner join, equal:[eq(test.t3.b, test.t2.b)]
  │ ├─TableReader(Build)	2.00	root		data:Selection
  │ │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.b))
  │ │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
  │ └─TableReader(Probe)	3.00	root		data:Selection
  │   └─Selection	3.00	cop[tikv]		not(isnull(test.t2.b))
  │     └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
  └─TableReader(Probe)	4.00	root		data:Selection
    └─Selection	4.00	cop[tikv]		not(isnull(test.t1.a))
      └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
explain format = 'brief' select * from t1 right join t2 on t1.a=t2.a join t3 on t2.b=t3.b;
id	estRows	task	access object	operator info
Projection	4.00	root		test.t1.a, test.t1.b, test.t2.a, test.t2.b, test.t3.a, test.t3.b
└─HashJoin	4.00	root		right outer join, equal:[eq(test.t1.a, test.t2.a)]
  ├─HashJoin(Build)	2.00	root		inner join, equal:[eq(test.t3.b, test.t2.b)]
  │ ├─TableReader(Build)	2.00	root		data:Selection
  │ │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.b))
  │ │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
  │ └─TableReader(Probe)	3.00	root		data:Selection
  │   └─Selection	3.00	cop[tikv]		not(isnull(test.t2.b))
  │     └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
  └─TableReader(Probe)	4.00	root		data:Selection
    └─Selection	4.00	cop[tikv]		not(isnull(test.t1.a))
      └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
explain format = 'brief' select * from t2 right join t3 on t3.a=t2.a right join t1 on t2.a=t1.a;
id	estRows	task	access object	operator info
HashJoin	4.00	root		right outer join, equal:[eq(test.t2.a, test.t1.a)]
├─Projection(Build)	2.00	root		test.t2.a, test.t2.b, test.t3.a, test.t3.b
│ └─HashJoin	2.00	root		inner join, equal:[eq(test.t3.a, test.t2.a)]
│   ├─TableReader(Build)	2.00	root		data:Selection
│   │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.a))
│   │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
│   └─TableReader(Probe)	3.00	root		data:Selection
│     └─Selection	3.00	cop[tikv]		not(isnull(test.t2.a))
│       └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
└─TableReader(Probe)	4.00	root		data:TableFullScan
  └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
explain format = 'brief' select * from (t1 left join t2 on t1.a=t2.a) left join (t3 left join t4 on t3.a=t4.a) on t2.a=t4.a;
id	estRows	task	access object	operator info
HashJoin	4.00	root		left outer join, equal:[eq(test.t2.a, test.t4.a)]
├─HashJoin(Build)	2.50	root		inner join, equal:[eq(test.t3.a, test.t4.a)]
│ ├─TableReader(Build)	2.00	root		data:Selection
│ │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.a))
│ │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
│ └─TableReader(Probe)	9990.00	root		data:Selection
│   └─Selection	9990.00	cop[tikv]		not(isnull(test.t4.a))
│     └─TableFullScan	10000.00	cop[tikv]	table:t4	keep order:false, stats:pseudo
└─HashJoin(Probe)	4.00	root		left outer join, equal:[eq(test.t1.a, test.t2.a)]
  ├─TableReader(Build)	3.00	root		data:Selection
  │ └─Selection	3.00	cop[tikv]		not(isnull(test.t2.a))
  │   └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
  └─TableReader(Probe)	4.00	root		data:TableFullScan
    └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
explain format = 'brief' select * from (t1 left join t2 on t1.a=t2.a) left join (t3 left join t4 on t3.a=t4.a) on t2.a=t3.a;
id	estRows	task	access object	operator info
HashJoin	4.00	root		left outer join, equal:[eq(test.t2.a, test.t3.a)]
├─HashJoin(Build)	2.50	root		left outer join, equal:[eq(test.t3.a, test.t4.a)]
│ ├─TableReader(Build)	2.00	root		data:Selection
│ │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.a))
│ │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
│ └─TableReader(Probe)	9990.00	root		data:Selection
│   └─Selection	9990.00	cop[tikv]		not(isnull(test.t4.a))
│     └─TableFullScan	10000.00	cop[tikv]	table:t4	keep order:false, stats:pseudo
└─HashJoin(Probe)	4.00	root		left outer join, equal:[eq(test.t1.a, test.t2.a)]
  ├─TableReader(Build)	3.00	root		data:Selection
  │ └─Selection	3.00	cop[tikv]		not(isnull(test.t2.a))
  │   └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
  └─TableReader(Probe)	4.00	root		data:TableFullScan
    └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
explain format = 'brief' select * from (t1 left join t2 on t1.a=t2.a) left join (t3 left join t4 on t3.a=t4.a) on t1.a=t4.a;
id	estRows	task	access object	operator info
HashJoin	4.00	root		left outer join, equal:[eq(test.t1.a, test.t4.a)]
├─HashJoin(Build)	2.50	root		inner join, equal:[eq(test.t3.a, test.t4.a)]
│ ├─TableReader(Build)	2.00	root		data:Selection
│ │ └─Selection	2.00	cop[tikv]		not(isnull(test.t3.a))
│ │   └─TableFullScan	2.00	cop[tikv]	table:t3	keep order:false
│ └─TableReader(Probe)	9990.00	root		data:Selection
│   └─Selection	9990.00	cop[tikv]		not(isnull(test.t4.a))
│     └─TableFullScan	10000.00	cop[tikv]	table:t4	keep order:false, stats:pseudo
└─HashJoin(Probe)	4.00	root		left outer join, equal:[eq(test.t1.a, test.t2.a)]
  ├─TableReader(Build)	3.00	root		data:Selection
  │ └─Selection	3.00	cop[tikv]		not(isnull(test.t2.a))
  │   └─TableFullScan	3.00	cop[tikv]	table:t2	keep order:false
  └─TableReader(Probe)	4.00	root		data:TableFullScan
    └─TableFullScan	4.00	cop[tikv]	table:t1	keep order:false
drop table if exists t3;
create table t3(a char(10), primary key (a));
insert into t3 values ('a');
select * from t3 where a > 0x80;
Error 1105: Cannot convert string '\x80' from binary to utf8mb4