Other Built-In Operators

Table 3-10 lists other SQL operators.

Table 3-10 Other SQL Operators

Operator	Purpose	Example
(+)	Indicates that the preceding column is the outer join column in a join. See "Outer Joins".	SELECT ename, dname FROM emp, dept WHERE dept.deptno = emp.deptno(+);
PRIOR	Evaluates the following expression for the parent row of the current row in a hierarchical, or tree-structured, query. In such a query, you must use this operator in the CONNECT BY clause to define the relationship between parent and child rows. You can also use this operator in other parts of a SELECT statement that performs a hierarchical query. The PRIOR operator is a unary operator and has the same precedence as the unary + and - arithmetic operators. See "Hierarchical Queries".	SELECT empno, ename, mgr FROM emp CONNECT BY PRIOR empno = mgr;