SQL Getting Started

Scalar Fullselects

A fullselect is a form of query that can be used in SQL statements. A scalar fullselect is a fullselect that returns one row containing only one value. Scalar fullselects are useful for retrieving data values from the database for use in an expression.

• The following example lists names of employees who have a salary greater than the average salary of all employees. The scalar fullselect within the query is the select statement in parentheses.

   
       SELECT LASTNAME, FIRSTNME
          FROM EMPLOYEE
          WHERE  SALARY > (SELECT AVG(SALARY)
                             FROM EMPLOYEE) 
  

• This example finds the average salary of the employees in the STAFF table and the average salary of the employees in the EMPLOYEE table.

   
       SELECT AVG(SALARY) AS "Average_Employee",
          (SELECT AVG(SALARY) AS "Average_Staff" FROM STAFF)
             FROM EMPLOYEE