You can treat Excel sheets as tables and perform SELECTs and JOINS like you would against a regular database. The language is Visual Basic (VBA to be exact). You can put the following code inside a Macro Sub. NAICS_CODE (Row 1) is a heading of one of the columns in the Results worksheet.
I did need to add the Microsoft ActiveX Data Objects 6.0 Library by going to Tools -> References in the VBA Project (the program that opens up when you edit a macro).
Dim cn As ADODB.Connection Set cn = New ADODB.Connection Dim rs As New ADODB.Recordset With cn .Provider = "Microsoft.Jet.OLEDB.4.0" .ConnectionString = "Data Source=C:\Users\zarar\Documents\researchdata.xls;" & _ "Extended Properties=Excel 8.0;" .Open End With 'Store all naicsCodes in an array Dim naicsCodes() As String 'Get all distinct NAICS codes Set rs = cn.Execute("SELECT DISTINCT NAICS_CODE FROM [Results$]") Dim i i = 0 Do Until rs.EOF ReDim Preserve naicsCodes(i + 1) naicsCodes(i) = rs.Fields("NAICS_CODE") i = i + 1 rs.MoveNext Loop rs.Close cn.Close