SQL against Excel Table returns nothing when "Where [ColumnName] = ""

I have a sub that filters a table from one worksheet to a new sheet using SQL.

The SQL statement: SELECT * FROM [STAMP$] WHERE [Approver_ID] = "my name"; WORKS.

The SQL statement SELECT * FROM [STAMP$] WHERE [Approver_ID] = ""; DOES NOT WORK. (returns an empty sheet)

What syntax would I use to get the blank rows from the table I am running the SQL against.

Thanks in advance.