You can test for a single bit set in a long integer or integer field using
the following algorithm:

( <value> \ (2^<bit>) ) mod 2

This expression will return 1 if the <bit> is set and 0 if <bit> is not
set. <bit> is numbered from 0 to 30 inclusive where <bit>=0 is the first
bit. <bit> values greater than 30 will not work with this algorithm because
Jet uses unsigned long integer values and 2^31 is one larger than the
largest unsigned long integer value and thus will cause numeric overflow
when the division is evaluated.

Note that the \ operator and not the / operator is used. The \ operator is
used for integer division. The / operator is used for floating point
division and will cause unexpected results when used with this algorithm.

You can check <bit> 31 for a long integer using the following algorithm:

iif( <value> < 0, 1, 0 )

This works because an unsigned long integer that is less than zero means
the highest order bit (bit 31 for a long) is set.

Suppose you have a table named Test and a long integer field named
TestFlags. You can use the following SQL statements to test to see if
the bit 11 is set in the TestFlags field

SELECT * FROM Test WHERE ([TestFlags]\2^11) mod 2 = 1

or replace 2^11 with 2048 to save some query calculation time:

SELECT * FROM Test WHERE ([TestFlags]\2048) mod 2 = 1

You can use the following SQL to test for bit 31

SELECT * FROM Test WHERE iif( [TestFlags] < 0, 1 ,0 ) = 1

but this SQL statement would be a much more efficient test for bit 31:

SELECT * FROM Test WHERE [TestFlags] < 0

Note that you can also create calculated columns in SQL to display the
results of one or more bit checks:

SELECT ([TestFlags]\2^11) mod 2 AS Bit11Set FROM Test

You can run the following ADO code to verify that this algorithm works
correctly over various ranges and with various bit flags. Note the test
requires a blank Microsoft Access database named C:\Db1.mdb and a reference
to Microsoft ActiveX Data Objects.

' START SAMPLE CODE
Sub VerifyBitTest()
Dim i As Long, min As Long, max As Long, bit As Long
Dim conn As New ADODB.Connection
Dim rs As New ADODB.recordset
conn.Open "DRIVER=Microsoft Access Driver (*.mdb);" & _
"MAXBUFFERSIZE=128;DBQ=c:\db1.mdb"
On Error Resume Next
conn.Execute "DROP TABLE Test"
On Error GoTo 0
conn.Execute "CREATE TABLE Test (TestFlags LONG)"
conn.Execute "INSERT INTO Test (TestFlags) VALUES (0)"
min = 2 ^ 0: max = 2 ^ 30: bit = 11
For i = min To max ' This could take a while.
rs.Open "SELECT (" & i & "\2^" & bit & _
") mod 2 AS BitSet FROM Test", conn
If rs!BitSet <> IIf((i And (2 ^ bit)) > 0, 1, 0) Then
MsgBox "Bit Test Failure!"
Exit Sub
End If
rs.Close
DoEvents
If i Mod 100 = 0 Then Debug.Print "Verified " & i & " of " & max
Next i
End Sub
' END SAMPLE CODE