Re: How to use SQL CASE

[Vernon Hamberg <vhamberg@xxxxxxxxxxxxxxx>]

Hi Alan

Someone else noted the extra comma after '9' in the list of values.

But that's not the main issue - I think there are a couple ways to do this.

First to explain what you have - this is a case1 style according to the 
documentation - you name a column after CASE, then have a value for that 
column after the WHEN - the key thing here is, it has to be a value that 
matches the column in data type and all.

I don't think I've ever tried to put a predicate after the WHEN as you 
did for the exception - in any "case", that might fail even if you get 
rid of the comma, because "not in" returns a boolean - a true/false - 
and this will not match a single-character data type that your column has.

Gary's suggestion to use ELSE is probably the simplest and lets you keep 
this style - the case1 style.

Another approach that lets you specify any conditionals is my choice, 
usually - and that would be to put the column name after WHEN with the 
test condition operators. IBM calls this case2 styele. Then you could 
have something like the last one you have, with the list.

So that would be something like this -

SELECT OPER,
case when BOX_SIZE = '1' then SEL0003 end as Count1,
case when BOX_SIZE = '2' then SEL0003 end as Count2,
case when BOX_SIZE = '3' then SEL0003 end as Count3,
case when BOX_SIZE = '4' then SEL0003 end as Count4,
case when BOX_SIZE = '5' then SEL0003 end as Count5,
case when BOX_SIZE = '6' then SEL0003 end as Count6,
case when BOX_SIZE = '7' then SEL0003 end as Count7,
case when BOX_SIZE = '8' then SEL0003 end as Count8,
case when BOX_SIZE = '9' then SEL0003 end as Count9,
case when BOX_SIZE = '0' then SEL0003 end as Count0,
case when BOX_SIZE not in ('0', '1', '2', '3', '4', '5', '6', '7'
                           '8', '9',) then
                    SEL0003 end as Count_Other
FROM file


But i still like the ELSE option better - that works with either style.

HTH
Vern

On 6/11/2015 8:31 AM, Alan Shore wrote:
> Hi everyone
> Before I forget - we are on V5r4 - hopefully moving up to the latest release very soon
> Here is my predicament
> I have a file that contains 3 fields
> User Profile name
> Box Size
> Count
>
> Box size can have valid values of '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
> I want to create a new file with the following
> SELECT OPER,
> case BOX_SIZE when '1'then SEL0003 end as Count1,
> case BOX_SIZE when '2'then SEL0003 end as Count2,
> case BOX_SIZE when '3'then SEL0003 end as Count3,
> case BOX_SIZE when '4'then SEL0003 end as Count4,
> case BOX_SIZE when '5'then SEL0003 end as Count5,
> case BOX_SIZE when '6'then SEL0003 end as Count6,
> case BOX_SIZE when '7'then SEL0003 end as Count7,
> case BOX_SIZE when '8'then SEL0003 end as Count8,
> case BOX_SIZE when '9'then SEL0003 end as Count9,
> case BOX_SIZE when '0'then SEL0003 end as Count0,
> case BOX_SIZE when not in ('0', '1', '2', '3', '4', '5', '6', '7'
>                             '8', '9',) then
>                      SEL0003 end as Count_Other
> FROM file
>
> It's the last case clause that I am having a problem with
> case BOX_SIZE when not in ('0', '1', '2', '3', '4', '5', '6', '7'
>                             '8', '9',) then
>                      SEL0003 end as Count_Other
>
>
>
> I want to capture the count if its not a valid value into its own field
>
> I hope this makes sense
> As always - all response gratefully accepted
>
>
>
> Alan Shore
> E-mail : ASHORE@xxxxxxxx
> Phone [O] : (631) 200-5019
> Phone [C] : (631) 880-8640
> 'If you're going through hell, keep going.'
> Winston Churchill