Function DConcat(ConcatColumns As String, Tbl As String, Optional Criteria As String = "", _ Optional Delimiter1 As String = "; ", Optional Delimiter2 As String = "; ", _ Optional Distinct As Boolean = True, Optional Sort As String = "", _ Optional Limit As Long = 0) ' Function by Patrick G. Matthews, basically embellishing an approach seen in many ' incarnations over the years ' Requires reference to Microsoft DAO library ' This function is intended as a "domain aggregate" that concatenates (and delimits) the ' various values rather than the more usual Count, Sum, Min, Max, etc. For example: ' ' Select Field1, DConcat("Field2", "SomeTable", "[Field1] = '" & Field1 & "'") AS List ' FROM SomeTable ' GROUP BY Field1 ' ' will return the distinct values of Field1, along with a concatenated list of all the ' distinct Field2 values associated with each Field1 value. ' ConcatColumns is a comma-delimited list of columns to be concatenated (typically just ' one column, but the function accommodates multiple). Place field names in square ' brackets if they do not meet the customary rules for naming DB objects ' Tbl is the table/query the data are pulled from. Place table name in square brackets ' if they do not meet the customary rules for naming DB objects ' Criteria (optional) are the criteria to be applied in the grouping. Be sure to use And ' or Or as needed to build the right logic, and to encase text values in single quotes ' and dates in # ' Delimiter1 (optional) is the delimiter used in the concatenation (default is ", "). ' Delimiter1 is applied to each row in the code query's result set ' Delimiter2 (optional) is the delimiter used in concatenating each column in the result ' set if ConcatColumns specifies more than one column (default is ", ") ' Distinct (optional) determines whether the distinct values are concatenated (True, ' default), or whether all values are concatenated (and thus may get repeated) ' Sort (optional) indicates whether the concatenated string is sorted, and if so, the ' columns used for the sort. As you would in an ORDER BY clause, use Asc or Desc to ' indicate whether the column is sorted ascending or descending. If Asc/Desc is ' omitted, Asc is assumed by the query engine ' Limit (optional) places a limit on how many items are placed into the concatenated string. ' The Limit argument works as a TOP N qualifier in the SELECT clause Dim rs As DAO.Recordset Dim SQL As String Dim ThisItem As String Dim FieldCounter As Long On Error GoTo ErrHandler ' Initialize to Null DConcat = Null ' Build up a query to grab the information needed for the concatenation SQL = "SELECT " & IIf(Distinct, "DISTINCT ", "") & _ IIf(Limit > 0, "TOP " & Limit & " ", "") & _ ConcatColumns & " " & _ "FROM " & Tbl & " " & _ IIf(Criteria <> "", "WHERE " & Criteria & " ", "") & _ IIf(Sort <> "", "ORDER BY " & Sort, "") Debug.Print SQL ' Open the recordset and loop through it: ' 1) Concatenate each column in each row of the recordset ' 2) Concatenate the resulting concatenated rows in the function's return value Set rs = DBEngine(0)(0).OpenRecordset(SQL, dbOpenForwardOnly) With rs Do Until .EOF ' Initialize variable for this row ThisItem = "" ' Concatenate columns on this row For FieldCounter = 0 To rs.Fields.Count - 1 ThisItem = ThisItem & Delimiter2 & Nz(rs.Fields(FieldCounter).value, "") Next ' Trim leading delimiter ThisItem = Mid(ThisItem, Len(Delimiter2) + 1) ' Concatenate row result to function return value DConcat = Nz(DConcat, "") & Delimiter1 & ThisItem .MoveNext Loop .Close End With ' Trim leading delimiter If Not IsNull(DConcat) Then DConcat = Mid(DConcat, Len(Delimiter1) + 1) GoTo Cleanup ErrHandler: ' Error is most likely an invalid database object name, or bad syntax in the Criteria DConcat = CVErr(Err.Number) Cleanup: Set rs = Nothing End Function
From novice to tech pro — start learning today.