syntax for storing chr(0) in sql server through vb


i am using the following code... Table test123 contains only one field name "a" whose database type is varchar(50)...

    Set conn = New ADODB.Connection
    conn.Open "eastman", "sa", "cosl"
    sql = "insert into test123 values('" & "'" & Chr(0) & "'" & "')"
    Set rs = conn.Execute(sql)
    conn.Close

But this is throwing an error..Plz suggest

You need a receptacle for the value, first of all. You need a table and a column.
Also, your string turns into (pairs of single-quotes on each side of a null character).

Try this:
    "NULL" should be a named constant that SQL recognizes. (Use a valid column name in place of "fldOne," one which can be set to a NULL value).