Solve SUDOKU by SQL

Oracle Database 11g Release 2 introduces a new feature called Recursive Subquery Factoring with the help of which you can solve your Sudoku.
Say you have a Sudoku like:


To solve this Sudoku you first have to transform this to a single string by appending all rows together:(give exact amount of spaces)

“53  7    6  195    98    6 8   6   34  8 3  17   2   6 6    28    419  5    8  79″

Past this string into a Recursive Subquery, run it and you get a new string with your solved Sudoku:

with x( s, ind ) as

( select sud, instr( sud, ' ' )

from ( select '53 7 6 195 98 6 8 6 34 8 3 17 2 6 6 28 419 5 8 79' sud from dual )

union all

select substr( s, 1, ind - 1 ) || z || substr( s, ind + 1 )

, instr( s, ' ', ind + 1 )

from x

, ( select to_char( rownum ) z

from dual

connect by rownum <= 9

) z

where ind > 0

and not exists ( select null

from ( select rownum lp

from dual

connect by rownum <= 9

)

where z = substr( s, trunc( ( ind - 1 ) / 9 ) * 9 + lp, 1 )

or z = substr( s, mod( ind - 1, 9 ) - 8 + lp * 9, 1 )

or z = substr( s, mod( trunc( ( ind - 1 ) / 3 ), 3 ) * 3

+ trunc( ( ind - 1 ) / 27 ) * 27 + lp

+ trunc( ( lp - 1 ) / 3 ) * 6

, 1 )

)

)

select s

from x

where ind = 0

/

\

The output:
534678912672195348198342567859761423426853791713924856961537284287419635345286179



This string can be transformed back to a nice display of the solution.

Solved in 1 Sec!….
My personal note: Sudoku is meant for human minds and not to be solved by a program. Hence you should enjoy solving them with your own minds. However you can use this if you are frozen at some point , unable to proceed further and frustration is about to begin…:)
Have a nice day!