Question

Please do NOT criticize me about this question, because it has been simplified.

Lets assume I got table CALENDAR with two columns: CLIENT_ID (INTEGER) and ENTRY_DATE(DATE) and this data:

+----------------------------+
| CLIENT_ID |   ENTRY_DATE   |
+-----------+----------------+
|   100     |    2012-01-03  |
|   100     |    2012-01-23  |
+-----------+----------------+

How can I using inline INSERT missing days ?

Answer 1

This query will insert the calendar holes for all clients:

INSERT INTO calendar (client_id, entry_date) (
    SELECT holes.client_id, holes.hole
    FROM (
            SELECT cal.client_id, cal.mn + level AS hole
            FROM (
                    SELECT client_id, MIN(entry_date) AS mn, MAX(entry_date) AS mx
                    FROM calendar
                    GROUP BY client_id
                    HAVING MAX(entry_date)>MIN(entry_date)+1
                 ) cal
            CONNECT BY cal.mn + level < cal.mx
            GROUP BY cal.client_id, cal.mn + level
        ) holes LEFT OUTER JOIN calendar c ON holes.client_id = c.client_id AND c.entry_date = hole
    WHERE
        c.entry_date IS NULL
)