在db2中如何使用Case Between

Question

I want to retrieve the ROLE from the table on the basis of SOA_VALUE. ie if the SOA_VALUE is in between 100 and 500 then ROLE should be RSM. If SOA_VALUE is more than 500 then ROLE should be TMM. The SOA_VALUE is coming from front end.

ROLE    CHANNEL    PLG     TRANTYPE     SOA_VALUE
ASM       GT       DETS    TRANSFER     0    
RSM       GT       DETS    TRANSFER     100  
TMM       GT       DETS    TRANSFER     500  

Ex: If the SOA_VALUE is 122,then role should come as RSM.

Please give me any suggestion/example query to retrieve the Role.Thanks.

Answer 1

Please try this:

 SELECT CHANNEL,PLG,TRANTYPE,SOA_VALUE
    FROM TABLE_X          
      WHERE ROLE = (CASE 
    WHEN (120 >= 100 AND 120 <=500) THEN 'RSM'
    WHEN 120 > 500 THEN 'TMM'
    ELSE NULL
                   end)

Replace 120 with the string value of the SOA_VALUE above.

Demo:

http://sqlfiddle.com/#!2/72d7f/3

Answer 2

How about this:

with t(input_soa_value) as (values 121) -- simulates input value
select role from table_x where soa_value = (
  select max(soa_value) from table_x, t where soa_value < input_soa_value
)