Concatenating new field makes everthing disappear

[projecttoday]

The following works in reading from my SQL Server table:

        Dim CMD As New SqlCommand
        CMD.Connection = conn

        CMD.CommandText = "SELECT tblPersons.id, "
        CMD.CommandText = CMD.CommandText & "CASE "
        CMD.CommandText = CMD.CommandText & "WHEN gobyn IS NULL "
        CMD.CommandText = CMD.CommandText & "THEN fn "
        CMD.CommandText = CMD.CommandText & "ELSE gobyn "
        CMD.CommandText = CMD.CommandText & "END "
        CMD.CommandText = CMD.CommandText & "+ ' ' + ln "
        CMD.CommandText = CMD.CommandText & "FROM tblPersons ORDER BY "
        CMD.CommandText = CMD.CommandText & "tblPersons.ln, tblPersons.gobyn, tblPersons.fn, tblPersons.suffix"

But when I add a field called suffix, all the records which don't have anything in that field come up blank.

        Dim CMD As New SqlCommand
        CMD.Connection = conn

        CMD.CommandText = "SELECT tblPersons.id, "
        CMD.CommandText = CMD.CommandText & "CASE "
        CMD.CommandText = CMD.CommandText & "WHEN gobyn IS NULL "
        CMD.CommandText = CMD.CommandText & "THEN fn "
        CMD.CommandText = CMD.CommandText & "ELSE gobyn "
        CMD.CommandText = CMD.CommandText & "END "
        CMD.CommandText = CMD.CommandText & "+ ' ' + ln + suffix "   '<--add the field here        CMD.CommandText = CMD.CommandText & "FROM tblPersons ORDER BY "
        CMD.CommandText = CMD.CommandText & "tblPersons.ln, tblPersons.gobyn, tblPersons.fn, tblPersons.suffix"

How can I correct this? The whole name,suffix included, does appear correctly when there is a value in suffix. The rest of the records are blank. Take out siffix and it's fine (except no suffix).