Question

I’m really not good with SQL and i just want to write a query that shows some log data in a chart.

I have a SQL Server table where i log requests made to a web service.

ID          RequestedFunction       RequestDateTime
1           'Confirm()'             2010-12-15 13:27:01.234
2           'Register()'            2010-12-16 12:27:00.678
3           'Confirm()'             2010-12-16 21:00:05.456

Now i’d like write a query that return me the number of requests made per day grouped by RequestedFunction; that return me a dataset like this.

Day          ConfirmFunctionRequests       RegisterFunctionRequests
15           1                             0
16           1                             1

Is this possible? All i could come up with so far is something like this,

;WITH CTE AS
(
SELECT id, 
    [Day] = CAST(day(requestDateTime) AS INT),
    RequestedFunction
FROM [Log]
WHERE month(RequestDateTime)=12 AND
year(RequestDateTime)=2010
)
SELECT [Day],COUNT(ID) AS [#Requests] FROM CTE GROUP BY [Day]

Which returns the number of requests per day, without differentiating between different types of requests. How can i write a query that counts the requests in to two different columns based on the value in ‘RequestedFunction’?

Answer 1

This can be done using a PIVOT but a quick and simple solution would be something like

DECLARE @Log TABLE(
        ID INT,
        RequestedFunction VARCHAR(50),
        RequestDateTime DATETIME
)
INSERT INTO @Log SELECT 1,'Confirm()','2010-12-15 13:27:01.234' 
INSERT INTO @Log SELECT 2,'Register()','2010-12-16 12:27:00.678'
INSERT INTO @Log SELECT 3,'Confirm()','2010-12-16 21:00:05.456'

SELECT  DATEADD(dd,0, DATEDIFF(dd,0,RequestDateTime)) DayValue,
        SUM(
                CASE
                    WHEN RequestedFunction = 'Confirm()' THEN 1
                    ELSE 0
                END 
            ) ConfirmFunctionRequests,
        SUM(
                CASE
                    WHEN RequestedFunction = 'Register()' THEN 1
                    ELSE 0
                END
            )RegisterFunctionRequests
FROM    @Log
GROUP BY DATEADD(dd,0, DATEDIFF(dd,0,RequestDateTime))