I came across this line of code in a SQL Report I am trying to fix. Could someone tell me what is the purpose of this.
DATEADD(dd, - DATEDIFF(dd, d.TxnDateTime, 1), 1) As TxnDate
To me it seems like it would cancel itself out.
It's removing the TIME portion of the DATETIME without changing the data type.
You can observe the different behavior here: SQL Fiddle
Again, not sure why you'd need to preserve the DATETIME type while removing the time, unless it predates the DATE datatype.