Oracle SQL

I have a table "Orders" and needs to retrieve all it's column names using an sql query. I know how to describe a table but i don't want it from describe I want to list them using SQL ...

What is the use of ADD, DROP and MODIFY Commands?

What are the differences between SQL and PL/SQL in Oracle?

What is the use of LIMIT and OFFSET in SQL?

I have this string (Oraask,Google,yahoo,new,old,etc) which is comma delimiter string and I need to get the value of nth for example the third value. expected output : yahoo

I need somebody to explain briefly why do we use bulk collect in Oracle

I have a column name called transaction_quantity and want to know the tables that have this column name and the owner of the table.