'INSERT ... SELECT' statements
            
The code that produces result rows expected that a duplicate row
error could not occur in INSERT ... SELECT statements with 
unfulfilled WHERE conditions. This may happen, however, if the 
SELECT list contains only aggregate functions.
Fixed by checking if an error occured before trying to send EOF
to the client.


mysql-test/r/insert_select.result:
  Bug#44306: Test result
mysql-test/t/insert_select.test:
  Bug#44306: Test case
sql/sql_select.cc:
  Bug#44306: Fix