Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Comment
t1	0	PRIMARY	1	a	NULL	NULL	NULL	NULL	
a	b
2	2
3	3
4	4
a	b
4	4
a	b
2	2
3	3
4	6
a	b
1	1
2	2
3	3
4	4
a
869751
802616
a
869751
802616
a
736494
a
736494
869751
a
226312
736494
802616
869751
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	range	uniq_id	uniq_id	4	NULL	4	where used; Using index
x	y
1	3
1	1
x	y	x	y
1	1	1	1
2	2	2	2
1	3	1	1
2	4	2	2
2	5	2	2
2	6	2	2
table	type	possible_keys	key	key_len	ref	rows	Extra
t1	ALL	x	NULL	NULL	NULL	6	
t2	eq_ref	y	y	4	t1.x	1	
max(a)
1
a	b
1	6
1	5
1	4
1	3
1	2
1	1
a	b
1	6
1	5
1	4
1	3
1	2
1	1
1	6
1	5
1	4
1	3
1	2
1	1
max(id)
1
max(id)
2
f1	f2
16	ted
12	ted
12	ted
12	ted
12	ted