Question: How do I check if the timestamp date of a record is before midnight today?

datediff is driving me nuts...

Answer: 
Try:

```
WHERE dtColumn < DATEADD(dd, 0, DATEDIFF(dd, 0, GETDATE()))

```
If ColumnName (column you are examining) is of datatype datetime, and NOT timestamp,
then the fastest approach is 

```
Select Case DateDiff(day, columnName, getDate()) 
   When 0 Then 'Today' Else 'Earlier' End
From TableName

```

assuming all dates values in ColumnName are now or earlier... 

Easiest way to think of datediff is that it counts the number of "boundarys" of the specified type that you have to pass over to get from one datetime to another...