Re: SQL join date field with numeric field

[Jason Abreu <jason.abreu@xxxxxxxxxxxxxxxxxxxx>]

Your comparison would be more reliable if you used both columns as DATE 
type.
Convert the numeric old column to CHAR(8) and extract year, month, and 
day to parse as date type and then compare.

SELECT *
FROM oldtable join newtable
       on newDate = DATE(SUBSTR(CHAR(oldDateAsNbr),1,4)||'-'||
                         SUBSTR(CHAR(oldDateAsNbr),5,2)||'-'||
                         SUBSTR(CHAR(oldDateAsNbr),7,2) )

Of course, this assumes you do not have any nulls in oldDateAsNbr and 
all values of oldDateAsNbr have a length of 8 and can convert to valid 
dates.

Jason Abreu
Abreu Innovations, Inc.
jason.abreu@xxxxxxxxxxxxxxxxxxxx
http://www.abreuinnovations.com/

On 2/8/2011 9:25 AM, David FOXWELL wrote:
> Hi,
>
> I need to join 2 tables, newtable and oldtable, using a date.
> In the old table, the date has been stored as a numeric value like this : 20101231
>
> I could join by extracting the year month and day from the new table and calculating a similar numeric representation, but is there a way of using the date function on the numeric value in the oldtable to give me a real date?
>
> Thanks