math-8queens-mysql

8 queens issue solution on MySQL

SQL Fiddle

MySQL 5.6 Schema Setup:

CREATE TABLE `t` (`i` INT AUTO_INCREMENT, PRIMARY KEY(`i`));
INSERT INTO t (i) VALUES(1),(2),(3),(4),(5),(6),(7),(8);

Query 1:

select
    t1.i as i1,
    t2.i as i2,
    t3.i as i3,
    t4.i as i4,
    t5.i as i5,
    t6.i as i6,
    t7.i as i7,
    t8.i as i8
from t t1
inner join t t2
on t2.i not in (t1.i,t1.i-1,t1.i+1)
inner join t t3
on t3.i not in (t1.i,t2.i,t2.i-1,t2.i+1,t1.i-2,t1.i+2)
inner join t t4
on t4.i not in (t1.i,t2.i,t3.i,t3.i-1,t3.i+1,t2.i-2,t2.i+2,t1.i-3,t1.i+3)
inner join t t5
on t5.i not in (t1.i,t2.i,t3.i,t4.i,t4.i-1,t4.i+1,t3.i-2,t3.i+2,t2.i-3,t2.i+3,t1.i-4,t1.i+4)
inner join t t6
on t6.i not in (t1.i,t2.i,t3.i,t4.i,t5.i,t5.i-1,t5.i+1,t4.i-2,t4.i+2,t3.i-3,t3.i+3,t2.i-4,t2.i+4,t1.i-5,t1.i+5)
inner join t t7
on t7.i not in (t1.i,t2.i,t3.i,t4.i,t5.i,t6.i,t6.i-1,t6.i+1,t5.i-2,t5.i+2,t4.i-3,t4.i+3,t3.i-4,t3.i+4,t2.i-5,t2.i+5,t1.i-6,t1.i+6)
inner join t t8
on t8.i not in (t1.i,t2.i,t3.i,t4.i,t5.i,t6.i,t7.i,t7.i-1,t7.i+1,t6.i-2,t6.i+2,t5.i-3,t5.i+3,t4.i-4,t4.i+4,t3.i-5,t3.i+5,t2.i-6,t2.i+6,t1.i-7,t1.i+7)

Results:

i	i	i	i	i	i	i	i
1	5	8	6	3	7	2	4
1	6	8	3	7	4	2	5
1	7	4	6	8	2	5	3
1	7	5	8	2	4	6	3
2	4	6	8	3	1	7	5
2	5	7	1	3	8	6	4
2	5	7	4	1	8	6	3
2	6	1	7	4	8	3	5
2	6	8	3	1	4	7	5
2	7	3	6	8	5	1	4
2	7	5	8	1	4	6	3
2	8	6	1	3	5	7	4
3	1	7	5	8	2	4	6
3	5	2	8	1	7	4	6
3	5	2	8	6	4	7	1
3	5	7	1	4	2	8	6
3	5	8	4	1	7	2	6
3	6	2	5	8	1	7	4
3	6	2	7	1	4	8	5
3	6	2	7	5	1	8	4
3	6	4	1	8	5	7	2
3	6	4	2	8	5	7	1
3	6	8	1	4	7	5	2
3	6	8	1	5	7	2	4
3	6	8	2	4	1	7	5
3	7	2	8	5	1	4	6
3	7	2	8	6	4	1	5
3	8	4	7	1	6	2	5
4	1	5	8	2	7	3	6
4	1	5	8	6	3	7	2
4	2	5	8	6	1	3	7
4	2	7	3	6	8	1	5
4	2	7	3	6	8	5	1
4	2	7	5	1	8	6	3
4	2	8	5	7	1	3	6
4	2	8	6	1	3	5	7
4	6	1	5	2	8	3	7
4	6	8	2	7	1	3	5
4	6	8	3	1	7	5	2
4	7	1	8	5	2	6	3
4	7	3	8	2	5	1	6
4	7	5	2	6	1	3	8
4	7	5	3	1	6	8	2
4	8	1	3	6	2	7	5
4	8	1	5	7	2	6	3
4	8	5	3	1	7	2	6
5	1	4	6	8	2	7	3
5	1	8	4	2	7	3	6
5	1	8	6	3	7	2	4
5	2	4	6	8	3	1	7
5	2	4	7	3	8	6	1
5	2	6	1	7	4	8	3
5	2	8	1	4	7	3	6
5	3	1	6	8	2	4	7
5	3	1	7	2	8	6	4
5	3	8	4	7	1	6	2
5	7	1	3	8	6	4	2
5	7	1	4	2	8	6	3
5	7	2	4	8	1	3	6
5	7	2	6	3	1	4	8
5	7	2	6	3	1	8	4
5	7	4	1	3	8	6	2
5	8	4	1	3	6	2	7
5	8	4	1	7	2	6	3
6	1	5	2	8	3	7	4
6	2	7	1	3	5	8	4
6	2	7	1	4	8	5	3
6	3	1	7	5	8	2	4
6	3	1	8	4	2	7	5
6	3	1	8	5	2	4	7
6	3	5	7	1	4	2	8
6	3	5	8	1	4	2	7
6	3	7	2	4	8	1	5
6	3	7	2	8	5	1	4
6	3	7	4	1	8	2	5
6	4	1	5	8	2	7	3
6	4	2	8	5	7	1	3
6	4	7	1	3	5	2	8
6	4	7	1	8	2	5	3
6	8	2	4	1	7	5	3
7	1	3	8	6	4	2	5
7	2	4	1	8	5	3	6
7	2	6	3	1	4	8	5
7	3	1	6	8	5	2	4
7	3	8	2	5	1	6	4
7	4	2	5	8	1	3	6
7	4	2	8	6	1	3	5
7	5	3	1	6	8	2	4
8	2	4	1	7	5	3	6
8	2	5	3	1	7	4	6
8	3	1	6	2	5	7	4
8	4	1	3	6	2	7	5