TABLE expression, querying collections tables [See also joins] aliases 2nd SELECT statements collections comparisons multilevel comparing, set operations comparisons customer, SELECT statement example entities hierarchies join queries joins key-preserved lines as relationships modifying UPDATE statement without WHERE clause moving data to nested NOT NULL columns, INSERT statement and object type partitions methods overview of pruning specifying self-referential integrity constraints XML tags, XML target strings templates, subpartition temporal data data types converting date/time formats literals modification of time zones terminology 2nd text date formatting fuzziness regular expressions backreferences collation elements equivalence classes functions named character classes time AM/PM indicators formats fractional seconds overview TIMESTAMP data type TIMESTAMP WITH LOCAL TIME ZONE data type TIMESTAMP WITH TIME ZONE data type rounding and truncating dates time zones database default overview session TIMESTAMP data type literals TIMESTAMP WITH LOCAL TIME ZONE data type, converting TO_CHAR function combining with TO_DATE function overview TO_DATE function combining with TO_CHAR function default date format overview specifying format TO_DSINTERVAL function TO_YMINTERVAL function tools, subtypes top N/bottom N queries (analytic ranking functions) traversing hierarchical trees trees, cycles identifying ignoring TRUNC function 2nd date pivot tables date ranges and truncating dates TRUST keyword, stored procedure two-digit years TZ_OFFSET function