General MySQL Oracle SQL Server

What Is a Subquery in Oracle

Q

What Is a Subquery in Oracle?

✍: FYIcenter.com

A

A subquery is a SELECT statement used as part of the selection criteria of the main SELECT statement. The subquery specified in the WHERE clause will be evaluated repeated on each row of the selection base table. The output of the subquery will be used in the final evaluation of the criteria. Usually, subqueries are used in the following Boolean operations:

  • "expression IN (subquery)"
  • "expression NOT IN (subquery)"
  • "EXISTS (subquery)"
  • "NOT EXISTS (subquery)"

 

⇒ Use Subqueries with the IN Operator in Oracle

⇐ Name Query Output Columns in Oracle

⇑ Understanding SQL SELECT Query Statements in Oracle

⇑⇑ Oracle Database Tutorials

2019-09-27, 3041🔥, 0💬

General MySQL Oracle SQL Server