You all have studied a chapter SET in your school days. SET is nothing but the collection of elements. Now, the reason to discuss this topic here is, some basic operations take place in SET, and hence, they play a vital role on Oracle when we talk about fields like testing, data science, analysis, etc.
The SET operations are:
- UNION: To find all the elements in two or more sets. However, avoiding the already existing value.
- INTERSECTION: To find the common elements
- UNION ALL: To check all the components in two or more Sets. However, including the duplicate values.
- MINUS: find the Elements of one set that are not present in the other set.
To understand the meaning of these terms kindly refer to the below diagram:
- 1,2,3 are those elements that are only present in SET A but not in SET B. Hence we can represent it as A - B.
- 5,6,7 are the common elements of both SET A and SET B that means it is the intersection point.
- 8,9,10 are those elements that are only present in SET B but not in SET A. Therefore it can be represented as B-A.
- 1,2,3,5,6,7,8,9,10 are all the elements that are present in both SET A and SET B, so we can explain it by the concept of Union.