Using case in field null

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Using case in field null

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#1 by (3 votes)
#2 by (3 votes)

3

I have the following structure tb_bulletin:

|Cod|boletim|dt_enviado|
| 1 |  N    | NULL     |
| 2 |  S    |24/08/2018|
| 3 |  S    | NULL     |
| 4 |  S    |23/08/2018|
| 5 |  S    |23/08/2018|
| 6 |  S    | NULL     |
| 7 |  N    | NULL     |
| 8 |  N    | NULL     |

I want to ONLY make an sql that brings me in two ways, depending on the parameter passed to the "bulletin" field.

Can I make a case in the where type?

select * from tb_boletim where
boletim = 'S' and
case
 when boletim = 'S' then dt_enviado is not null
 when boletim = 'N' then dt_enviado null
end

Expected result:

|Cod|boletim|dt_enviado|
| 2 |  S    |24/08/2018|
| 4 |  S    |23/08/2018|
| 5 |  S    |23/08/2018|

or

|Cod|boletim|dt_enviado|
| 1 |  N    | NULL     |
| 7 |  N    | NULL     |
| 8 |  N    | NULL     |

sql firebird case firebird-2.5

asked by anonymous 24.08.2018 / 15:19

2 answers

3

I do not know if I fully understood the issue ...

Is this what you want?

select 
   Cod
  ,boletim
  ,case when boletim='S' then dt_enviado else NULL END dt_enviado 
FROM tb_boletim

/*WHERE BOLETIM='S'*/
/*WHERE BOLETIM='N'*/

You can add a WHERE clause to filter or not according to the BULLETIN field

24.08.2018 / 15:32

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score 3 · Accepted Answer

Yes, you can. The received parameter ( @parametro_boletim ) will control whether the validation will be done with it equal to S or N ):

SELECT * 
FROM tb_boletim 
WHERE boletim = @parametro_boletim
  ((boletim = 'S' and dt_enviado is not null) OR
   (boletim = 'N' and dt_enviado null))