The problem is that when we make conditon for
grouped result const part of condition is cut off.
It happens because some parts of 'having' condition
which refer to outer join become const after
make_join_statistics. These parts may be lost
during further having condition transformation
in JOIN::exec. The fix is adding 'having'
condition check for const tables after
make_join_statistics is performed.


mysql-test/r/having.result:
  test case
mysql-test/t/having.test:
  test result
sql/sql_select.cc:
  added 'having' condition check for const tables
  after make_join_statistics is performed.