Table schema:
CREATE TABLE Certificate (eid VARCHAR, aid VARCHAR); CREATE TABLE Employee (name VARCHAR, eid VARCHAR); CREATE TABLE Employee (name VARCHAR); CREATE TABLE Aircraft (aid VARCHAR, name VARCHAR)

Question: Show names for all employees who do not have certificate of Boeing 737-800.
SQL: SELECT name FROM Employee EXCEPT SELECT T1.name FROM Employee AS T1 JOIN Certificate AS T2 ON T1.eid = T2.eid JOIN Aircraft AS T3 ON T3.aid = T2.aid WHERE T3.name = "Boeing 737-800"