DSQL, PSQL

WITH RECURSIVE
S1 AS (
  SELECT '112-233-445 95' AS SNILS FROM RDB$DATABASE UNION ALL
  SELECT '165-300-180 28' AS SNILS FROM RDB$DATABASE UNION ALL
  SELECT '999-999-999 95' AS SNILS FROM RDB$DATABASE
),
S2 AS (
  SELECT S1.SNILS, REPLACE(SUBSTRING(S1.SNILS FROM 1 FOR 11),'-','') N, RIGHT(S1.SNILS,2) TO_CHECK
  FROM S1
),
R AS(
  SELECT 1 I FROM RDB$DATABASE UNION ALL SELECT R.I+1 FROM R WHERE R.I<9
),
C AS (
  SELECT S2.SNILS, S2.N, S2.TO_CHECK
        ,SUM((10-R.I) * CAST( SUBSTRING(S2.N FROM R.I FOR 1) AS SMALLINT )) DSUM
  FROM   S2 CROSS JOIN R
  GROUP BY S2.SNILS,S2.N,S2.TO_CHECK
),
D AS (
  SELECT C.SNILS, C.N, C.TO_CHECK
        ,IIF( C.DSUM < 100, C.DSUM, IIF(C.DSUM IN(100,101), 0,  COALESCE(NULLIF(MOD(C.DSUM, 101), 100),0)  ) ) CHECKED
  FROM C
)
SELECT D.SNILS, D.TO_CHECK, D.CHECKED, IIF(D.TO_CHECK = D.CHECKED, 'OK', 'X') RESULT
FROM D

Таблоид, http://www.sql.ru/forum/actualutils.aspx?action=gotomsg&tid=1145734&msg=17348339