Difference Between oracle 10g,12C & 18C

Database Compersion
Oracle10g	Oracle 12C	Oracle18C
Data Guard improvements	DataGuard enhancements	Active DataGuard added
Realtime apply and log compressions	Detection of gasps and automatic resolution	Standby Database can now be queried where redo apply is active
Backup and Recovery	Backup and Recovery	Improved Manageability
.    Data Pump Added	Block level recovery	ASM Cluster FileSystem (ACFS) Introduced
	Improved reporting and automation	Virtual Columns added
Security	Security	Security
Password is not case sensitive	Password case sensitive	Password  complexity
	Improved reporting and automation
	Oracle 12C supports In-memory aggregation, which improves of queries and  Reduce the CPU Usage	In-Memory in Oracle Database 18c also allows you to place data from external tables in the column store. Also It can now scan compression units in-parallel to double the speed of data read
single index	Multiple indexes	Virtual Indexes
Table space Rename	Move Datafile
Need Database Shutdown to change archive log mode	No need to shutdown database for changing archive log mode.
	Oracle 12c introduced a lot of online partition features	Oracle 18c, we can MERGE PARTITIONS online and maintain the indexes.
Not Possible	-	Oracle 18c users to create temporary database objects that are automatically dropped at the end of a transaction or a session.
	Optimized more database .We can add other application also there which will save licence cost of db server and system cost.	Optimized more database .We can add other application also there which will save licence cost of db server and system cost