SQL EXISTS clause Statements

In this chapter you will learn:
What is EXISTS clause?
Syntax of EXISTS clause
Example of EXISTS clause

What is EXISTS clause?

The EXISTS clause helps to check the existence of a subquery according to the condition specified and passes the status of existence to the outer query. It always returns a Boolean value (True or False).

Syntax of EXISTS clause

SELECT column_name from table_name where EXISTS (SELECT column_name from table_name where conditional_expression)

Example of EXISTS clause

select employeeid, title from humanresources.employee where
exists (select * from humanresources.employeedepartmenthistory
where employeeid=humanresources.employee.employeeid and departmentid=4)
  exists clause example screen shot
SUMMARY

In this chapter, you have learned about EXISTS clause with an example. In the next chapter you will learn about BETWEEN clause.

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