Automatically Add Missing Records With SQL

Hi,

I have a table that contains 2 columns. The first column has the datetime, and the second has a value (see the "Before" table). In my SELECT query I want to select all records like 0:00:00 <= Date <= 0:40:00. However the missing 10-minutes value 0:30:00 should be automatically inserted with value = NULL.

Before:

Code:

Date Value
------------------- -------------------
13/12/2004 0:00:00 15
13/12/2004 0:10:00 17
13/12/2004 0:20:00 21
13/12/2004 0:40:00 12
13/12/2004 0:50:00 13



After:

Code:

Date Value
------------------- -------------------
13/12/2004 0:00:00 15
13/12/2004 0:10:00 17
13/12/2004 0:20:00 21
13/12/2004 0:30:00 NULL
13/12/2004 0:40:00 12



Can anyone help me? Thanks.