Loop through employee numbers and see if certain date falls within a period - vba

Question

Who can help a beginner out. I've added two screenshots to make my story clearer.
My excel sheet is two tabs. One is 'calculation' and other is 'project'.
What i'd like to know is how to program the following in vba:
In the calculation tab there is a employee number in column E. I have to look if that number also is written in the projects tab. If so i need to know if the date of the calculation tab falls within the start and end date in the projects tab. If so then write the info if that row to the empty columns in the calculation tab.
Another problem arises when an employee works multiple jobs in the projects tab. I guess there needs to be another loop in here:
If the date from calculation tab doesn't fall in the period from start to end in the projects tab, is there another row with the same employee number and maybe it falls within that period.
I hope i made my story clear. I know what the steps should be, just not how to program it. I hope someone is able to help me with this.

Answer 1

Since your screenshots appear to be Excel for Windows consider an SQL solution using Windows' JET/ACE Engine (.dll files) as you simply need to join the two worksheets with a WHERE clause for date filter. In this approach you avoid any need for looping and use of arrays/collections.
To integrate below, add a new worksheet called RESULTS as SQL queries on workbooks are read-only operations and do not update existing data. A LEFT JOIN is used to keep all records in Calculations regardless of matches in Projects but matched data will populate in empty columns. Results should structurally replicate Calculations. Adjust column names in SELECT, ON, and WHERE clauses as required (as I cannot clearly read column names from screenshots). Finally, a very important item: be sure date columns are formatted as Date type.
Dim conn As Object, rst As Object
Dim strConnection As String, strSQL As String
Dim i As Integer
Set conn = CreateObject("ADODB.Connection")
Set rst = CreateObject("ADODB.Recordset")
' OPEN DB CONNECTION
strConnection = "DRIVER={Microsoft Excel Driver (*.xls, *.xlsx, *.xlsm, *.xlsb)};" _ '
& "DBQ=C:\Path\To\Workbook.xlsx;"
conn.Open strConnection
' OPEN QUERY RECRDSET
strSQL = "SELECT t1.*, t2.[Project] AS [Which Project], t2.[Customer] As [Which Customer]," _
& " t2.[Start], t2.[End planned], t2.[Hours per week]" _
& " FROM [Calculation$A$3:$D$1048576] t1" _
& " LEFT JOIN [Projects$A$3:$J$1048576] t2" _
& " ON t1.EmployeeNum = t2.EmployeeNum" _
& " WHERE t1.[Date] BETWEEN t2.Start AND t2.[End planned];"
rst.Open strSQL, conn
' COLUMNS
For i = 1 To rst.Fields.Count Worksheets("RESULTS").Cells(3, i) =
rst.Fields(i - 1).Name
Next i
' DATA ROWS
Worksheets("RESULTS").Range("A4").CopyFromRecordset rst
rst.Close
conn.Close
Set rst = Nothing
Set conn = Nothing

Answer 2

it would be great to let us know, what you have done so far. I think the easiest way for a beginner is to just use two loops. One for the calculation and one for the projects tab.
Then you can start to develop your functionality. Use a "row counter" for each worksheet and iterate trough the rows. Here is an example pseudo code:
Dim lRowCountCalc as Long
Dim lRowCountPrj as Long
lRowCountCalc = 1
lRowCountPrj = 1
do
do
If Table2.Range("A" & lRowCountPrj).Value = Table1.Range("E" & lRowCountPrj).Value Then
If ... dates are equal
'Do some stuff
End if
End If
lRowCountPrj = lRowCountPrj +1
Loop Until lRowCountPrj = 5000 Or Table2.Range("A" & lRowCountPrj).text = ""
lRowCountCalc = lRowCountCalc +1
Loop Until lRowCountCalc = 5000 Or Table1.Range("A" & lRowCountCalc).text = ""
Just check for each employee number in calculation if there is a the same number in the current row in projects. If so, do your checks and fill in the information you need. If there is more than one project, you will find it also because all rows will be checked.
But be careful. This is very expensive because this code iterates for each row in projects over all rows in calculation. But for the beginning I would do it like this.