Q:

Differences between MySQL and Oracle databases

What are the differences between MySQL and Oracle databases. I know both are RDBMS, both use SQL as Query language and both are developed by Oracle. So what are the differences between these two technically? 

A:

I used Oracle in Deuth Bank for 1,5 years, and some experience with MySQL on other job.
In general, Oracle is much more powerful and is a deeper RDBMS, which allows you to write any complex system. That's why it is used in banking, military, and science fields.
MySQL - is light, simple RDBMS, it is very well for web, for example small internet shop, your personal web page, or page of a school. More complex web often use RDBMS PostgreSQL.
Oracle allows you to use packages (often on PL/SQL), coursurs (same as subselect), PL/SQL language, Roles, snapshot, synonym, tablespace.
Also Oracle has more advanced data types, and a bit different datatypes.
For example:
BIGINT (8 Bytes) In MySQL, in Oracle called - NUMBER (19,0).
For what I miss in Oracle is select * from dual, wherein dual is a default virtual table in Oracle. 
For more deep comparison, please check compare table on Oracle's website:
https://docs.oracle.com/cd/E12151_01/doc.150/e12155/oracle_mysql_compared.htm#i1027526

