Although Oracle's other flashback options are not available in Express Edition, Flashback Query is. According to the question on it, no other database has this feature that allows a select statement to query data as of a point in time in the past. Flashback data can be joined with current data and inserted into current tables making it useful for undo type operations, temporary changes, and comparing changes made by a method in one place.
Some other things that some other databases do not have that Oracle Express Edition does:
- Packages
- AuthID Current User vs. Definer
- Check Constraints
- Deferrable Constraints
- Compressed Indexes
- Reverse Indexes
- Public Synonyms
- Compressed Tables
- External Tables
- Global Temporary Tables
- Nested Tables
- Date addition and subtraction
- Hierarchical Queries
- Multiset Operators
- Database and Schema level Triggers - After ServerError, After Startup, Before Logoff, DDL, etc.
- Before Insert/Update/Delete statement and row level triggers.
- After Insert/Update/Delete statement and row level triggers.
- Analytic Functions CORR, COVAR_COUNT, COVARSAMP, CUME_DIST, FIRST_VALUE, LAG, LAST_VALUE, LEAD, PERCENT_RANK, PERCENTILE_CONT, PERCENTILE_DISC, RATIO_TO_REPORT, REGR_COUNT, REGR_INTERCEPT, REGR_SLOPE, STDDEV_SAMP, VAR_SAMP, etc.
- Collection Functions CARDNALITY, COLLECT, POWERMULTISET
- Date-Time Functions ADD_MONTHS, CURRENT_TIMESTAMP, EXTRACT, GREATEST, LAST_DAY, LEAST, MONTHS_BETWEEN, NEW_TIME, NEXT_DAY, TRUNC.
- Data Mining Functions
- Model Functions
- Null Functions LNNVL, NVL2.
- Numeric Functions CORR, COVAR_POP, COVAR_SAMP, CUME_DIST, DENSE_RANK, MEDIAN, NANVL, PERCENT_RANK, PERCENTILE_CONT, PERCENTILE_DISC, RANK, REMAINDER, SINH, STATS_BINOMIAL_TEST, STATS_CROSSTAB, SSTDDEV_SAMP, TANH, TRUNC, VAR_POP, etc.
- String Functions INITCAP, QUOTE_DELIMITERS, TRANSLATE, TREAT, TRIM.
- XML functions
- Clob datatype (Up to 128 TB)
- Create or Replace Syntax.
- DML Triggers are part of transaction.
- Multi-Platform (Linux and Windows)
