修改两处，让SQLite求解数独SQL在datafusion上运行

原始SQL

sql 复制代码

WITH RECURSIVE
  input(sud) AS (
    VALUES('....754..........8.8.19....3....1.6........34....6817.2.4...6.39......2.53.2.....'), 
    ('3.........5.7.3..8....28.7.7......43...........39.41.54..3..8..1...4....968...2..')
  ),
  digits(z, lp) AS (
    VALUES('1', 1)
    UNION ALL SELECT
    CAST(lp+1 AS TEXT) , lp+1 FROM digits WHERE lp<9
  ),
  x(s, ind) AS (
    SELECT sud, instr(sud, '.') FROM input
    UNION ALL
    SELECT
      substr(s, 1, ind-1) || z || substr(s, ind+1),
      instr( substr(s, 1, ind-1) || z || substr(s, ind+1), '.' )
     FROM x, digits AS z
    WHERE ind>0
      AND NOT EXISTS (
            SELECT 1
              FROM digits AS lp
             WHERE z.z = substr(s, ((ind-1)/9)*9 + lp, 1)
                OR z.z = substr(s, ((ind-1)%9) + (lp-1)*9 + 1, 1)
                OR z.z = substr(s, (((ind-1)/3) % 3) * 3
                        + ((ind-1)/27) * 27 + lp
                        + ((lp-1) / 3) * 6, 1)
         )
  )
SELECT s FROM x WHERE ind=0;

报错：

ValueError: Error during planning: Projections require unique expression names but the expression "CAST(digits.lp + Int64(1) AS Utf8View)" at position 0 and "digits.lp + Int64(1)" at position 1 have the same name. Consider aliasing ("AS") one of them.

将CAST(lp+1 AS TEXT) , lp+1分别加上别名，以上错误消失，又出来如下错误：

Exception: DataFusion error: type_coercion

caused by

Execution error: Cannot access field at argument 1: type Utf8 is not Struct, Map, or Null

python 复制代码

s="""
WITH RECURSIVE
  input(sud) AS (
    VALUES('....754..........8.8.19....3....1.6........34....6817.2.4...6.39......2.53.2.....'), 
    ('3.........5.7.3..8....28.7.7......43...........39.41.54..3..8..1...4....968...2..')
  ),
  digits(z, lp) AS (
    VALUES('1', 1)
    UNION ALL SELECT
    CAST(lp+1 AS TEXT) as z, lp+1 as lp FROM digits WHERE lp<9
  ),
  x(s, ind) AS (
    SELECT sud, instr(sud, '.') FROM input
    UNION ALL
    SELECT
      substr(s, 1, ind-1) || z || substr(s, ind+1),
      instr( substr(s, 1, ind-1) || z || substr(s, ind+1), '.' )
     FROM x, digits AS z
    WHERE ind>0
      AND NOT EXISTS (
            SELECT 1
              FROM digits AS lp
             WHERE z.z = substr(s, ((ind-1)/9)*9 + lp, 1)
                OR z.z = substr(s, ((ind-1)%9) + (lp-1)*9 + 1, 1)
                OR z.z = substr(s, (((ind-1)/3) % 3) * 3
                        + ((ind-1)/27) * 27 + lp
                        + ((lp-1) / 3) * 6, 1)
         )
  )
SELECT s FROM x WHERE ind=0;
"""
from datafusion import SessionContext
ctx = SessionContext()
ctx.sql(s)

这是由于datafusion把z.z中的第一个 z 当作了列名, 而不是表别名, 将表别名取一个不和列名重复的值，就好了

sql 复制代码

WITH RECURSIVE
  input(sud) AS (
    VALUES('....754..........8.8.19....3....1.6........34....6817.2.4...6.39......2.53.2.....'), 
    ('3.........5.7.3..8....28.7.7......43...........39.41.54..3..8..1...4....968...2..')
  ),
  digits(z, lp) AS (
    VALUES('1', 1)
    UNION ALL SELECT
    CAST(lp+1 AS TEXT) as z, lp+1 as lp FROM digits WHERE lp<9
  ),
  x(s, ind) AS (
    SELECT sud, instr(sud, '.') FROM input
    UNION ALL
    SELECT
      substr(s, 1, ind-1) || z || substr(s, ind+1),
      instr( substr(s, 1, ind-1) || z || substr(s, ind+1), '.' )
     FROM x, digits AS d
    WHERE ind>0
      AND NOT EXISTS (
            SELECT 1
              FROM digits AS lp
             WHERE d.z = substr(s, ((ind-1)/9)*9 + lp, 1)
                OR d.z = substr(s, ((ind-1)%9) + (lp-1)*9 + 1, 1)
                OR d.z = substr(s, (((ind-1)/3) % 3) * 3
                        + ((ind-1)/27) * 27 + lp
                        + ((lp-1) / 3) * 6, 1)
         )
  )
SELECT s FROM x WHERE ind=0;

这次能输出正确的结果

复制代码

+-----------------------------------------------------------------------------------+
| s                                                                                 |
+-----------------------------------------------------------------------------------+
| 387419526259763418641528379716285943594631782823974165472396851135842697968157234 |
| 693875412145632798782194356357421869816957234429368175274519683968743521531286947 |
+-----------------------------------------------------------------------------------+