Difference between EXISTS and IN in SQL?

Question

What is the difference between the EXISTS and IN clause in SQL?

When should we use EXISTS, and when should we use IN

Answer 1

The Exists keyword evaluates true or false, but IN keyword compare all value in the corresponding sub query column. Another one Select 1 can be use with Exists command. Example:

SELECT * FROM Temp1 where exists(select 1 from Temp2 where conditions...)

But IN is less efficient so Exists faster.