Question

I have a query that I am executing in C# that is taking way too much time:

string Query = "SELECT COUNT(HISTORYID) FROM HISTORY WHERE YEAR(CREATEDATE) = YEAR(GETDATE()) ";
Query += "AND MONTH(CREATEDATE) = MONTH(GETDATE()) AND DAY(CREATEDATE) = DAY(GETDATE()) AND USERID = '" + EmployeeID + "' ";
Query += "AND TYPE = '5'";

I then use SqlCommand Command = new SqlCommand(Query, Connection) and SqlDataReader Reader = Command.ExecuteReader() to read in the data. This is taking over a minute to execute from C#, but is much quicker in SSMS.

I see from google searching you can do something with CompiledQuery, but I’m confused whether I can still use the built in SQL functions YEAR, MONTH, DAY, and GETDATE.

If anyone can show me an example of how to create and call a compiled query using the built in functions, I will be very grateful! Thanks in advance.

Answer 1

even if you have an index on CREATEDATE, it will not use it. You need to change your date logic to floor the GETDATE() datetime to a day like this:

WHERE CREATEDATE>=DATEADD(day,DATEDIFF(day,0,GETDATE()),0)
   AND CREATEDATE<DATEADD(day,DATEDIFF(day,0,GETDATE()),0)+1 ...

When you use the function on the column, like: YEAR(CREATEDATE), you prevent an index from being used.