SQL查询-根据数值返回文本

Question

I am trying to work out a query where the query will perform a count (total) on a specific column. If the count is greater than 0, I want to display YES and display NO if the returned count is zero.

So, if I a query as this:

SELECT COUNT(ProblemID)
FROM dbo.ProblemInfo
WHERE (ProblemID IN (100,101,309,305,205,600,500)) AND (DEPID = '10866')

that will actually be a subquery, how do I get the subquery to display "YES" when the returned count is greater than 0 and NO if the count is 0?

I appreciate any insight and help.

Answer 1

select isnull(
    SELECT MAX('YES')
    FROM dbo.ProblemInfo
    WHERE ProblemID IN (100,101,309,305,205,600,500)
    AND DEPID = '10866'),
'NO')

This is a trick to return either YES if there's at least one matching row, or null if not.

The wrapping isnull call then turns a null into a NO

Answer 2

try

SELECT CASE 
WHEN (SELECT COUNT(ProblemID) FROM dbo.ProblemInfo WHERE (ProblemID IN (100,101,309,305,205,600,500)) AND (DEPID = '10866')) > 0 
THEN 'YES' 
ELSE 'NO' END 
FROM YourTable

Answer 3

Here's an alternate way of querying that.

IF EXISTS(
            SELECT *
            FROM dbo.ProblemInfo
            WHERE (ProblemID IN (100,101,309,305,205,600,500))
            AND (DEPID = '10866')
        )
    BEGIN
        SELECT 'Yes'
    END
ELSE
    BEGIN
        SELECT 'No'
    END

What I like about this method is that, for enormous data-sets, it should be noticeably faster.

Answer 4

you can use case when.

SELECT 
case 
when COUNT(ProblemID) = 0 then 'NO'
else 'YES'
end
FROM dbo.ProblemInfo WHERE (ProblemID IN (100,101,309,305,205,600,500)) AND (DEPID = '10866')