SQL for EMPTY records

[Seth]

I am trying to open a recordset using the following SQL
statement:

"SELECT * FROM MyTable WHERE MyDate = ''"

I want all the records that don't have a valid date...in
the database, there is either a date value or "N/A" to
indicate that there is presently no date.

Under normal conditions (i.e., selecting all the records
in MyTable), all the records in the MyDate field that
have "N/A" values are returned as empty strings.

What is the proper SQL syntax for getting all the non-
date values in the MyDate field?

Thanks,

Seth