Re: when timestamp is null

thank you very much, that worked wonderfully.
i didn't even think about the end date being null.

mikeo


At 04:16 PM 7/12/00 -0400, Tom Lane wrote:
>mikeo <mikeo@spectrumtelecorp.com> writes:
>>   i want to update rows of a table where the column defined
>> as type timestamp is null.  
>
>> update cust set cust_svc_start_dt = cust_svc_end_dt -1
>> where cust_svc_start_dt is null;
>
>> ERROR:  Unable to convert null timestamp to date
>
>I suspect the problem here is that cust_svc_end_dt is also null in those
>records, or some of them anyway, and the expression
>"cust_svc_end_dt::date - 1" is what's failing.
>
>IMHO it's a bug that the current implementation of timestamp-to-date
>kicks out an error for a null timestamp; it should just play nice and
>return a null date.  (This is already fixed for 7.1, BTW.)
>
>In the meantime you could do something with a CASE expression to
>substitute an appropriate result when cust_svc_end_dt is null:
>
>UPDATE cust SET cust_svc_start_dt = CASE
>	WHEN cust_svc_end_dt IS NULL THEN whatever
>	ELSE cust_svc_end_dt -1
>	END
>WHERE ...
>
>			regards, tom lane
>