Find out missing dates in table

Question

Hi,
I've a table that sould have a record for day with sales info, but for some reason there are missing dates, is there any way i could find out witch dates are missing.
Table Example:
sales_date | value
2010-01-01 | 20
2010-01-02 | 30
2010-01-04 | 40
The output of the query for the example above sould return only the missing date (2010-01-03).
Thanks in advance

Answer 1

How about (I wouldn't use this if your concerned about speed!)...
WITH src_data
       AS (SELECT TO_DATE('2010-01-01', 'YYYY-MM-DD') sales_date FROM DUAL
           UNION ALL
           SELECT TO_DATE('2010-01-02', 'YYYY-MM-DD') sales_date FROM DUAL
           UNION ALL
           SELECT TO_DATE('2010-01-04', 'YYYY-MM-DD') sales_date FROM DUAL),
    date_table
       AS (SELECT     LEVEL, MAX(sales_date) - LEVEL + 1 my_date
           FROM       src_data
           CONNECT BY LEVEL <=
                         (SELECT MAX(sales_date) - MIN(sales_date) + 1
                          FROM   src_data)
           GROUP BY   LEVEL
           ORDER BY   my_date ASC)
SELECT *
FROM   date_table
WHERE  NOT EXISTS (SELECT 1
                   FROM   src_data
                   WHERE  sales_date = my_date)Cheers
Ben