创建案例表达时出现的问题

Question

I am facing issues when I try to create a case expression with a group function condition along with normal column conditions.

Table: STG

+ -------+--------+------+----------+
| Ref_ID | Actual | Paid | Reason   |
+ -------+--------+------+----------+
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 0      | 480  | TRAINING |
| H1     | 0      | 0    |          |
| H1     | 360    | 0    |          |
| H1     | 360    | 0    |          |
+ -------+--------+------+----------+

Already the code is like below:

Explanation: If Actual hrs per day exceeds 480 then that needs to be taken as 480. ie. 8hrs/day * 60 =480. then the sum of actual is extended 1440 then that needs to be deducted from the sum of actual hrs.

In this same query, I have to sum the all actuals along with paid (paid hrs if reason is Training)

 SELECT
    CASE WHEN (SUM(CASE WHEN (ACTUAL)>480 THEN 480 ELSE (ACTUAL) END))>1440 THEN
    ((SUM(CASE WHEN (ACTUAL)>480 THEN 480 ELSE (ACTUAL) END))-1440) ELSE 0
    END SINGLE_RATE
    FROM STG WHERE REF_ID='H1'
    GROUP BY REF_ID;

I tried to modify like below:

SELECT
    CASE WHEN (SUM(CASE WHEN (ACTUAL)>480 THEN 480 ELSE (ACTUAL) END)+(case when reason = 'training' then paid else 0 end ))>1440 THEN
    ((SUM(CASE WHEN (ACTUAL)>480 THEN 480 ELSE (ACTUAL) END)+(case when reason = 'training' then paid else 0 end ))-1440) ELSE 0
    END SINGLE_RATE
    FROM STG WHERE REF_ID='H1'
    GROUP BY REF_ID;

but getting below error:

    ORA-00979: not a GROUP BY expression
    00979. 00000 -  "not a GROUP BY expression"
    *Cause:
    *Action:

Also tried like:

SELECT
    (sum ( (CASE WHEN (ACTUAL)>480 THEN 480 ELSE (ACTUAL) END) + case when reason = 'training' then paid else 0 end )-1440) SINGLE_RATE
    FROM STG WHERE REF_ID='H1'
    GROUP BY REF_ID
    having sum ( (CASE WHEN (ACTUAL)>480 THEN 480 ELSE (ACTUAL) END) + case when reason = 'training' then paid else 0 end )>1440;

but the paid amount is not getting calculated. Only actual is added.

Please give your suggestions.

Answer 1

From your business rules, you always want to include actual in the sum() calculation but only include paid when the reason is 'training' . That rule is quite easy to express in a case statement. In addition you have a cap that actual cannot exceed 480. That rule can be satisfied with a least() function:

select ref_id
      , sum ( least(actual, 480) + case when reason = 'training' then paid else 0 end ) as tot
from stg
group by ref_id
/

To be frank I am still not clear what you are trying to achieve with the 1440; life would be easier if you had posted some sample data which covered all the cases you wanted to handle and your desired output derived from that sample data. But I am going to guess anyway:

with cte as (
    select ref_id
          , sum ( least(actual, 480) + case when reason = 'training' then paid else 0 end ) as tot
    from stg
    group by ref_id
    )
select ref_id
       case 
          when tot <= 1440 then tot
          else tot - 1440
       end as adjusted_tot
from cte
/

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As before, if this does not provide the answer you want please edit your question. The clearer your requirement the more likely you are to get a timely answer.