Split multi-value field into different rows using SQL in Microsoft Access - sql

Question

I’ve got a simple table in Microsoft Access that looks like this:
Primary Key
Applications List
123
<Value>|<Value>,<Value>|<Value>
456
<Value>|<Value>,<Value>|<Value>
I need to break out the list of applications into separate rows using the “,” as a delimiter so the end result is a table that looks like this:
Primary Key
Applications List
123
<Value>|<Value>
123
<Value>|<Value>
456
<Value>|<Value>
456
<Value>|<Value>
I’ve tried using the Split function but can’t figure out how to split on the “,” and output the results to a different row like the second table above. I would greatly appreciate your help figuring this one out. Thanks so much!

Answer 1

If you can put a limit on the length of Application List you can build a number table
CREATE TABLE NumTable (ID integer)
up-front with as many rows as there are characters in the longest Application List. Assuming that the longest [Application List] is 1000 characters long, ID=1, ID=2, ..., ID=1000), and then use something like this:
select T.[Primary Key],
mid(T.AL,NT.ID+1
, iif(instr(NT.ID+1,t.AL,',')>0
, instr(NT.ID+1,t.AL,',')-1-nt.ID,1000)) as
from (select [Primary Key], ',' & [Application List] as AL from tblYourTable) as T
inner join
NumTable as NT
on mid(t.AL,NT.ID,1)=','
You can build the number table in EXCEL and paste it; or write a little VBA routine, or even create it dynamically (*).
I can't imagine it performing very well if the volume is high.
Let us know how you proceed!
(*)Generate numbers 1 to 1000000 in MS Access using SQL

Answer 2

If you setup a Table1 and a Table2 with the same field names, you can run this function to do it for you - it basically loops through Table1 records, splits the Applications List into multiple fields and then inserts new records for each field.
Public Sub SplitDataIntoNewTable()
Const DATA_SEPARATOR As String = ","
Dim qdf As DAO.QueryDef
Dim rsOld As DAO.Recordset
Dim rsNew As DAO.Recordset
Dim i As Integer
Dim lngNumAdded As Long
Dim lngKey As Long
Dim strList As String
Dim strNewList As String
Dim varLists As Variant
Set rsOld = CurrentDb.OpenRecordset("Table1", dbOpenDynaset, dbReadOnly)
Set rsNew = CurrentDb.OpenRecordset("Table2", dbOpenDynaset)
With rsOld
While Not .EOF
lngKey = ![Primary Key]
strList = ![Applications List]
varLists = Split(strList, DATA_SEPARATOR)
With rsNew
For i = LBound(varLists) To UBound(varLists)
' Add new record for every list split out of old data
.AddNew
' Note that this CANNOT actually be defined as a PRIMARY KEY - it will have duplicates
![Primary Key] = lngKey
![Applications List] = varLists(i)
lngNumAdded = lngNumAdded + 1
.Update
Next i
End With
.MoveNext
Wend
rsNew.Close
.Close
End With
MsgBox "Added " & lngNumAdded & " New Records"
Set rsOld = Nothing
Set rsNew = Nothing
End Sub
For example I had Table1 look like this:
And resulting Table2 ended up like this