How to set controlsource of a textbox from SQL - sql

Question

I have a subform bound to a SQL statement. Inside the subform, I have a few text boxes bound to the fields of this SQL. However, I have another text box that needs to be bound to a field from a different SQL statement with criteria from the first one. My code looks like below:
Dim subform As Object
Dim formFilter As String
formFilter = "SELECT * FROM my_table_1"
Set subform = Me!my_subform.Form
subform.RecordSource = formFilter
subform.field1.ControlSource = "tb1f1"
subform.field2.ControlSource = "tb1f2"
...
subform.f3.ControlSource = "= SELECT TOP 1 tb2f3 FROM my_table_2 WHERE tb2f1 = '" & [tb1f1] & "' AND tb2f2 = '" & [tb1f2] "' ORDER BY tb2f4"
I cannot use a DLOOKUP function here directly, because I need to sort the table result.
Thanks in advance for your help.

Answer 1

I think I would simply create a little function to go get the result you want. It would probably be best to simply rework DLookup in your own function and add sort but I won't do that here.
First the form code. Notice I am not setting the recordsource, just the value which may not be what you want.
subform.f3 = fGet_tb2f3([tb1f1], [tb1f2])
Then the function code (put in your own error handling)
Public Function fGet_tb2f3(tblf1 as String,tblf2 as String) as String
Dim rst as dao.recordset
Dim db as database
set db = currentdb
set rst = db.openrecordset("SELECT TOP 1 tb2f3 FROM my_table_2 WHERE tb2f1 = '" & tb1f1 & "' AND tb2f2 = '" & tb1f2 "' ORDER BY tb2f4",dbopensnapshot
if not rst is nothing then
if not rst.eof then fGet_tb2f3 = rst!tb2f3
rst.close
set rst = nothing
end if
db.close
set db = nothing
end Function

Answer 2

You can't bind controls on the same form to 2 different recordsets. The only thing you could do is pull data from 2 different recordsets, but that's probably not the best way to do anything.
In order to do that, you'd have to create a second recordset and grab that value in it. Something like:
Dim db as Database
Dim rec as Recordset
Set db = CurrentDB
Set rec = db.OpenRecordset("SELECT TOP 1 tb2f3 FROM my_table_2 WHERE tb2f1 = '" & [tb1f1] & "' AND tb2f2 = '" & [tb1f2] "' ORDER BY tb2f4")
Me.MyControlName = rec(0)