What is Semijoin? How to implement it in SQL?

Question

Q. What is Semijoin? How to implement it in SQL?

Answer 1

Ans is 

Semijoin returns records from the left table which match with the right table. Even if there are multiple matching records on the right table, the Semijoin returns a single record of the left table. It prevents duplications. Semijoin can be implemented using the WHERE EXISTS clause.