SQL Server Group By Month

Question

I have a table which has this schema

ItemID    UserID    Year    IsPaid    PaymentDate  Amount
1         1         2009    0         2009-11-01  300
2                


        

Answer 1

DECLARE @start [datetime] = 2010/4/1;

Should be...

DECLARE @start [datetime] = '2010-04-01';

The one you have is dividing 2010 by 4, then by 1, then converting to a date. Which is the 57.5th day from 1900-01-01.

Try SELECT @start after your initialisation to check if this is correct.