Power Query or Get & Transform (In Excel 2016) lets you perform a series of steps to transform your Excel data.  One of the steps it allows you to take is to split your date into year, month and day for easier processing.
STEP 1: Select your data and turn it into an Excel Table by pressing the shortcut Ctrl + T or by going to Insert > Table
STEP 2: Go to Data > Get & Transform > From Table (Excel 2016) or Power Query > Excel Data > From Table (Excel 2013 & 2010)
Excel 2016:
 
Excel 2013 & 2010:
STEP 3: This will open up the Power Query Editor. Let us now get the Year, Month and Day.
Make sure the Order Date column is selected. Go to Add Column > From Date & Time > Date > Year> Year
Make sure the Order Date column is selected. Go to Add Column > From Date & Time > Date > Month > Month
Make sure the Order Date column is selected. Go to Add Column > From Date & Time > Date > Day > Day
STEP 4: Click Close & Load from the Home tab and this will open up a brand new worksheet in your Excel workbook with the updated records!
You now have your dates split to Year, Month and Day!
How to Split the Date in Excel Using Power Query
