do $$
declare 
  r0 record;
  r record;
  _a int[] :=    '{8,0,0,1,0,0,3,0,2,0,0,3,0,6,4,0,0,0,6,1,0,0,0,8,0,4,7,9,4,0,0,0,0,8,2,6,0,0,0,7,0,2,0,0,0,5,2,1,0,0,0,0,3,9,7,8,0,6,0,0,0,5,1,0,0,0,9,2,0,6,0,0,4,0,6,0,0,0,0,0,0}';
  t_ text;
begin
for r0 in (
  with recursive a (s, ind) as 
                 (select sud, 
                         (select si 
                            from generate_subscripts(sud, 1) si 
                           where sud[si]=0 
                           order by si limit 1) 
                    from (select _a as sud) f
                   union all
                  select a.s[1:ind-1]||i||a.s[ind+1:array_upper(s,1)], 
                         (select si 
                            from generate_subscripts(s, 1) si 
                           where si>=ind+1 and s[si]=0
                           order by si limit 1)
                    from a, generate_series(1,9) i
                   where ind > 0
                     and not exists ( select lp 
                                        from generate_series(1,9) lp
                                       where i in ((select s[ trunc( ( ind - 1 ) / 9 )::int * 9 + lp ] ),
                                                   (select s[ mod( ind - 1, 9 )::int - 8 + lp * 9 ] ),
                                                   (select s[ mod( trunc( ( ind - 1 ) / 3 )::int, 3 )::int * 3
                                                            +(trunc( ( ind - 1 ) / 27 ) * 27 + lp)::int
                                                            +(trunc( ( lp - 1 ) / 3 ) * 6)::int ])))
                 )

select s, row_number() over () as ind
  from a
 where ind is null) loop     

 t_ := 'var №'||r0.ind||chr(13)||chr(10)||rtrim(repeat('---+', 9), '+')||chr(13)||chr(10);
 for r in (select r0.s[i:i+8] as a
             from generate_series(1, array_upper(r0.s,1), 9) i)
 loop
  t_ := t_||' '||array_to_string(r.a, ' | ')||chr(13)||chr(10);
  t_ := t_||rtrim(repeat('---+', 9), '+')||chr(13)||chr(10);
 end loop;

 raise info '%', t_;
end loop;
end;$$;

INFO:  var №1
---+---+---+---+---+---+---+---+---
 8 | 5 | 4 | 1 | 7 | 9 | 3 | 6 | 2
---+---+---+---+---+---+---+---+---
 2 | 7 | 3 | 5 | 6 | 4 | 1 | 9 | 8
---+---+---+---+---+---+---+---+---
 6 | 1 | 9 | 2 | 3 | 8 | 5 | 4 | 7
---+---+---+---+---+---+---+---+---
 9 | 4 | 7 | 3 | 1 | 5 | 8 | 2 | 6
---+---+---+---+---+---+---+---+---
 3 | 6 | 8 | 7 | 9 | 2 | 4 | 1 | 5
---+---+---+---+---+---+---+---+---
 5 | 2 | 1 | 4 | 8 | 6 | 7 | 3 | 9
---+---+---+---+---+---+---+---+---
 7 | 8 | 2 | 6 | 4 | 3 | 9 | 5 | 1
---+---+---+---+---+---+---+---+---
 1 | 3 | 5 | 9 | 2 | 7 | 6 | 8 | 4
---+---+---+---+---+---+---+---+---
 4 | 9 | 6 | 8 | 5 | 1 | 2 | 7 | 3
---+---+---+---+---+---+---+---+---

INFO:  var №2
---+---+---+---+---+---+---+---+---
 8 | 5 | 4 | 1 | 7 | 9 | 3 | 6 | 2
---+---+---+---+---+---+---+---+---
 2 | 7 | 3 | 5 | 6 | 4 | 1 | 9 | 8
---+---+---+---+---+---+---+---+---
 6 | 1 | 9 | 2 | 3 | 8 | 5 | 4 | 7
---+---+---+---+---+---+---+---+---
 9 | 4 | 7 | 3 | 5 | 1 | 8 | 2 | 6
---+---+---+---+---+---+---+---+---
 3 | 6 | 8 | 7 | 9 | 2 | 4 | 1 | 5
---+---+---+---+---+---+---+---+---
 5 | 2 | 1 | 4 | 8 | 6 | 7 | 3 | 9
---+---+---+---+---+---+---+---+---
 7 | 8 | 2 | 6 | 4 | 3 | 9 | 5 | 1
---+---+---+---+---+---+---+---+---
 1 | 3 | 5 | 9 | 2 | 7 | 6 | 8 | 4
---+---+---+---+---+---+---+---+---
 4 | 9 | 6 | 8 | 1 | 5 | 2 | 7 | 3
---+---+---+---+---+---+---+---+---