Why doesn't the Oracle optimizer use my index?
Querying too much data
Most Oracle developers know that an index is useful when you can use it to restrict your result set to a small number of the total rows in a table.
So, the obvious side…
Subquery in Oracle:
Sub queries are one of advance queries in oracle.
Types of advance queries:
• Sub Queries
• Hierarchical Queries
• Set Operators
Sub queries are know as the query called from another query or another subquery. It can …