Database Table Operations- A Performance Consideration

While doing database table operations i.e. SQLS in ABAP; we should follow the below sequence form performance consideration

SQL Join/Sub Query
|
V
View in Data Dictionary
|
V
Select for all enttries
|
V
Select using internal Tables
|
V
Nested selectes

Note:
1. Joins can only be used for fields in transparent tables. Most commonly used Joins are Inner Join & Left Outer Join
2. A subquery is a SELECT command within another SELECT, specified in the WHERE condition, that checks whether data from a database table or view meets certain conditions. Subqueries are available as of SAP Release 4.0. In addition, subqueries can be used in UPDATE and DELETE statements as well.