(This is because conds may not be a constant)
This bug caused a failure in the test suite for select.test becasue for prepared statements in one case a 'constant sub query' was not regarded as a constant
Sanja will as a separate task check if we can fix that the sub query can be recognized as a constant
Bug #12217


sql/sql_select.cc:
  We have also to test 'conds' even if there was no tables.
  (This is because conds may not be a constant)
  This bug caused a failure in the test suite for select.test becasue for prepared statements in one case a 'constant sub query' was not regarded as a constant
  Sanja will as a separate task check if we can fix that the sub query can be recognized as a constant