postgresql SELECT 1 value and count(value), but LIMIT the count to 1

Question

So far I have this as my SQL Query:

SELECT value, count(value) over () as TOTAL from listofvalues GROUP BY value 

The result look like that:

value|TOTAL 

IS18-0001| 6
IS18-0002| 6
IS18-0003| 6
IS18-0004| 6
IS18-0005| 6
IS18-0006| 6

What I want the result to look like would be more like that:

value|TOTAL 

IS18-0001| 6
IS18-0002|
IS18-0003|
IS18-0004|
IS18-0005|
IS18-0006|

Basically I want to LIMIT the total to 1, but can't seems to find a solution, any idea? Is that even possible?

Answer 1

You can check for row_number and set other rows to null (or '')

SELECT value, 
case row_number() over () when 1 then count(value) over () else null end as TOTAL 
from listofvalues GROUP BY value 

Answer 2

Please try below query. I just added a row number to your query.

Select Value,case when RN=1 then Total else '' END Total 
From(
select value,Cast(Total as varchar) Total,ROW_NUMBER() over (order by value) RN
from(
SELECT value, 
       count(value) over () as TOTAL
 from #listofvalues GROUP BY value 
 )A)B 

Answer 3

It would seem that you don't need the group by , so I would start with:

SELECT value,
       (CASE WHEN row_number() over (order by value) = 1 
             THEN count(*) over ()
        END) as TOTAL
FROM listofvalues ;

The GROUP BY is only needed if you have multiple rows with the same value. If you have duplicates, your query is doing something quite specific -- counting the number of distinct values, while listing each value exactly once. It is not counting the number of rows in the original data.