[TIP] Use COALESCE instead of nested IFNULL calls.

[Ivan Smahin]

Hello jda,

Tuesday, March 15, 2005, 2:40:22 PM, you wrote:

>>Here is just a tip.
>>
>>   Example:
>>
>>   SELECT
>>         IFNULL(f1, IFNULL(f2,f3)) as 'ff'
>>   FROM
>>       t1
>>
>>   Here we just need to get first not-null value using field-order - f1,f2,f3.
>>
>>   The issue seems to be a little bit bulky.
>>   You can use COALESCE instead of. It seems more clear and concisely.
>>   Look:
>>
>>   SELECT
>>         COALESCE(f1, f2, f3) as 'ff'
>>   FROM
>>       t1
>>
>>

j> Hi Ivan,

j> I tried this select:

j> s = "select *,theDateSortMethod,COALESCE(authors, editors, title) as
j> 'ff' from thereferences where hit>0 ORDER BY ff,theDateSortMethod"

j> and got the error:

j> Feature Not Supported

j> Jon
j> _______________________________________________
j> Valentina-beta mailing list
j> Valentina-beta at lists.macserve.net
j> http://lists.macserve.net/mailman/listinfo/valentina-beta

It is just because of "ORDER BY ff".
We work to get this feature workable now.

-- 
Best regards,
 Ivan                            mailto:IvanSmahin at public.kherson.ua