LAST_DAY function 2nd leaf nodes identifying leaf nodes hierarchical queries LEFT outer joins 2nd less than (<) operator less than or equal to (<=) operator LEVEL pseudocolumn levels hierarchical queries number of, finding lifecycles LIKE operator lines, definition of list partitioning literals dates DAY TO SECOND interval INTERVAL TIMESTAMP YEAR TO MONTH interval local indexes LOCALTIMESTAMP function logical models compared to physical models, entities and logical operators, WHERE clause loops, FOR