VBA SQL - Changing code from 'Insert Into' to 'Update' table - sql

Question

I have looked and looked for an answer and cannot translate the answers to my specific code. I have some code for an Access Database that works as an INSERT TO but I want it to UPDATE a table. I cannot get it to run after changing it to UPDATE.
The following code works and what it does is add values that meet the criteria to the beginning of an existing table. But I want it to update the existing blank column "O_StateRegion" in a table called "Sonoco2016_xlsx". My efforts of switching INSERT INTO to UPDATE have failed. (See second example of code for my efforts)
Private Sub InsertStateRegion()
On Error GoTo InsertRegions_Err
Dim db As Database
Dim rs As Recordset
Dim strSQL As String
Set db = CurrentDb
Set rs = db.OpenRecordset("Select [OriginState] from [Sonoco2016_xlsx];")
rs.MoveFirst
While Not rs.EOF
strSQL = "UPDATE [Sonoco2016_xlsx] ([O_StateRegion])"
strSQL = strSQL & " SELECT [StateRegion] FROM [tblStates]"
strSQL = strSQL & " WHERE [tblStates].[StateAbbrev]='" & rs![OriginState] & "' "
db.Execute (strSQL), dbFailOnError
rs.MoveNext
Wend
rs.Close
Set rs = Nothing
Set db = Nothing
btnInsertRegions_Exit:
Exit Sub
InsertRegions_Err:
MsgBox Err.Description & " in btnInsertRegions"
Resume btnInsertRegions_Exit
End Sub
Below are my efforts to convert it to UPDATE
Private Sub btnInsertRegions_Click()
On Error GoTo InsertRegions_Err
Dim db As Database
Dim rs As Recordset
Dim strSQL As String
Set db = CurrentDb
Set rs = db.OpenRecordset("Select [OriginState] from [Sonoco2016_xlsx];")
rs.MoveFirst
While Not rs.EOF
strSQL = "UPDATE [Sonoco2016_xlsx] ([O_StateRegion])"
strSQL = strSQL & " SET [Sonoco2016_xlsx].[O_StateRegion]=[tblStates].[StateRegion]"
strSQL = strSQL & " WHERE [tblStates].[StateAbbrev] = '" & rs![OriginState] & "' "
db.Execute (strSQL), dbFailOnError
rs.MoveNext
Wend
rs.Close
Set rs = Nothing
Set db = Nothing
btnInsertRegions_Exit:
Exit Sub
InsertRegions_Err:
MsgBox Err.Description & " in btnInsertRegions"
Resume btnInsertRegions_Exit
End Sub

Answer 1

The correct syntax for what you want to achieve is
UPDATE [Sonoco2016_xlsx]
INNER JOIN [tblStates]
ON [tblStates].[StateAbbrev] = [Sonoco2016_xlsx].[OriginState]
SET [Sonoco2016_xlsx].[O_StateRegion]=[tblStates].[StateRegion];
which you would execute without using a recordset.
Note, however, that this will only work if [StateAbbrev] has a unique index, e.g. if it is the primary key of [tblStates]. Otherwise, the update would be ambiguous.
Moreover, it is not possible to use a subquery in the set statement like
SET [Sonoco2016_xlsx].[O_StateRegion]=(SELECT [StateRegion]
FROM = [tblStates]
WHERE [StateAbbrev] = rs![OriginState])
because subqueries are prohibited in UPDATE statements.

Answer 2

Here is the answer that worked for me thanks to M Doerner!
Private Sub btnInsertRegions_Click()
On Error GoTo InsertRegions_Err
Dim db As Database
Dim rs As Recordset
Dim strSQL As String
Set db = CurrentDb
Set rs = db.OpenRecordset("Select [OriginState] from [Sonoco2016_xlsx];")
rs.MoveFirst
While Not rs.EOF
strSQL = "UPDATE [Sonoco2016_xlsx] INNER JOIN [tblStates]"
strSQL = strSQL & " ON [tblStates].[StateAbbrev] = [Sonoco2016_xlsx].[OriginState]"
strSQL = strSQL & " SET [Sonoco2016_xlsx].[O_StateRegion]=[tblStates].[StateRegion]"
db.Execute (strSQL), dbFailOnError
rs.MoveNext
Wend
rs.Close
Set rs = Nothing
Set db = Nothing
btnInsertRegions_Exit:
Exit Sub
InsertRegions_Err:
MsgBox Err.Description & " in btnInsertRegions"
Resume btnInsertRegions_Exit
End Sub