Oracle 案例报表查询

Question

I am working on an Oracle Query to find if Diagnostic Pack is installed. Query is working fine.

Select case when currently_used = 'TRUE' then 1
else 0
end DIAGNOSTICS_package
from dba_feature_usage_statistics
where name like '%Diagnostic Pack%'
and CURRENTLY_USED = 'TRUE'

In the Output I need to add another Column Installed. So if currently_used = 'TRUE' I need the output to be displayed as below.

DIAGNOSTICS_package INSTALLED
1                   YES

I am running into an issue with the INSTALLED Column in the case statement. Please advise.

Thanks

Answer 1

The simplest answer to your question is, just add another CASE expression for the second column:

Select case when currently_used = 'TRUE' then 1
else 0
end DIAGNOSTICS_package,
case when currently_used = 'TRUE' then 'YES' else 'NO' end INSTALLED
from dba_feature_usage_statistics
where name like '%Diagnostic Pack%'
and CURRENTLY_USED = 'TRUE'

I don't really get why you want two columns that tell you the same thing in different ways.

I also don't get why you need a CASE statement at all, since you have and CURRENTLY_USED = 'TRUE' as part of the query conditions.

But maybe there is a larger context where these things make sense.

Answer 2

Based on your where clause, you don't need a case expression:

Select 1 as DIAGNOSTICS_package,
       'YES' as INSTALLED
from dba_feature_usage_statistics
where name like '%Diagnostic Pack%' and
      CURRENTLY_USED = 'TRUE'

You are already filtering on CURRENTLY_USED = 'TRUE' .