Re: SQL join date field with numeric field

[Charles Wilt <charles.wilt@xxxxxxxxx>]

Consider that using a function against a column in a table precludes
the use of an index over that column for that table...

If the tables are of similar sizes, then it probably doesn't matter....

If one table is larger than the other and there's an index over the
column in the larger table, then you probably want to convert the
column from the smaller table to the format of the larger.

Going from date to YYYYMMDD numeric is best done with a UDF such as
iDate, but it can be done with SQL
select dec(replace(char(current_date, iso),'-',''),8,0)
from sysibm/sysdummy1


HTH,
Charles

On Tue, Feb 8, 2011 at 9:25 AM, David FOXWELL <David.FOXWELL@xxxxxxxxx> 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
>
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