Easy to read code

Not a suggestion.

the numbers from whole range from 0 to n, which squared contain 1 as a digit

this: the numbers of interest are should be written as follow:

the numbers of interest are (the numbers from whole range from 0 to n, containg 1 as a digit)

it would be more clear.

0, 2, 3, etc. squared don't contain 1, that's why they weren't shown (they aren't numbers of interest there)

Please let me know the explanation to this part:

nb_dig(25, 1):
the numbers of interest are
1, 4, 9, 10, 11, 12, 13, 14, 19, 21 which squared are 1, 16, 81, 100, 121, 144, 169, 196, 361, 441
so there are 11 digits 1 for the squares of numbers between 0 and 25.

if k is between 0 and n, I assume it should be:

rawK = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25}

instead of:

rawK = {1, 4, 9, 10, 11, 12, 13, 14, 19, 21 }

?

in select satatement what exactly do then part? is there any possibility to use given labels?

Finished with 'panjabi' code style.
IMHO it should be ZULU format first (23:15 -> twenty-three fifteen, 14:00 -> fourteen hundrets)

Personally I do not understand why to use postgreSQL, in comparision to MariaDB it is like going for shopping with tank.

For mysql coders it gives a hard time. Somehow it should be possible to determine the other variants are possible or not (like mysql language implementation)

I love the oneline shots in python but it gives me hard time, everytime I try to make the solution that way I get the failure and finish with if a == b: Bleeh