on 5/30/01 23:12, Steven at srt /at/ bigpond D.O.T net.au wrote:
> Hi Ruslan,
>
> I have a table with fields A, B, C and D.
>
> I want to search through the table for records where D=foo.
>
> However, depending on the value of the field C for the matching records, I
> want to retrieve either the field A or B for that record, according to the
> rule:
>
> If C=0 then
> i want to retrieve field A
> else
> i want to retrieve field B
> end
>
> Can I do this conditional selection within the sql statement, something
> like this?:
> Select (A if C=0 else B) from Table where D=foo.
>
> I think this might be possible using the Control flow function
> IF( exp1, exp2, exp3 ) that I see in the valentina sql documentation, but
> I'm not sure?
>
> Something like
> "Select IF(C=0,A,B) from Table where D=foo"???
Yes you need to use this IF( exp1, exp2, exp3 ) function.
but you can not use it directly in SQL query.
You must at first define a BaseObject Method using it, for example
D = "if( C = 0, A, B)"
Now in SQL you can do:
SELECT D FROM T Where ...
> The idea being that the resulting cursor will already have the correct
> field that I need for each record, rather than having to retrieve both
> fields and then testing each record in the cursor in a WS loop to select
> the appropriate field for the record.
--
Best regards,
Ruslan Zasukhin
-------------------------
Paradigma.
e-mail: ruslan@paradigmasoft.com
web : http://www.paradigmasoft.com
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