Optimized SELECT DISTINCT ... ORDER BY ... LIMIT
Fixed reference to uninitalized variable


mysql-test/r/distinct.result:
  Updated results for new tests
mysql-test/r/func_math.result:
  Fixed test of RND()
mysql-test/r/innodb.result:
  Updated results for new tests
mysql-test/r/null.result:
  Updated results for new tests
mysql-test/t/distinct.test:
  New distinct test
mysql-test/t/func_math.test:
  Fixed test of RND()
mysql-test/t/innodb.test:
  Test for bugs
mysql-test/t/null.test:
  TEst for bugs
sql/field.h:
  Change of NULL handling to avoid error messages
sql/field_conv.cc:
  Change of NULL handling to avoid error messages
sql/item.cc:
  Change of NULL handling to avoid error messages
sql/item.h:
  Change of NULL handling to avoid error messages
sql/item_cmpfunc.cc:
  Change of NULL handling to avoid error messages
sql/item_func.cc:
  Change of NULL handling to avoid error messages
sql/item_func.h:
  Cleaned up RND() handling
sql/item_timefunc.cc:
  Change of NULL handling to avoid error messages
sql/item_timefunc.h:
  Change of NULL handling to avoid error messages
sql/opt_range.cc:
  Fixed bug in <=> NULL
sql/password.c:
  Indentation cleanup
sql/sql_base.cc:
  Change of NULL handling to avoid error messages
sql/sql_class.cc:
  Fixed reference to uninitalized variable
sql/sql_handler.cc:
  Change of NULL handling to avoid error messages
sql/sql_select.cc:
  Change of NULL handling to avoid error messages
  Optimized SELECT DISTINCT ... ORDER BY ... LIMIT
sql/sql_select.h:
  Change of NULL handling to avoid error messages
sql/unireg.cc:
  Change of NULL handling to avoid error messages