Comparison Conditions

Comparison conditions compare one expression with another. The result of such a comparison can be TRUE, FALSE, or UNKNOWN.

Note: Large objects (LOBs) are not supported in comparison conditions. However, you can use PL/SQL programs for comparisons on CLOB data.

Table 5-2 lists comparison conditions.

Table 5-2   Comparison Conditions

Type of Condition	Purpose	Example
=	Equality test.	SELECT * FROM employees WHERE salary = 2500;
!= ^= < > ¬=	Inequality test. Some forms of the inequality condition may be unavailable on some platforms.	SELECT * FROM employees WHERE salary != 2500;
> <	"Greater than" and "less than" tests.	SELECT * FROM employees WHERE salary > 2500; SELECT * FROM employees WHERE salary < 2500;
>= <=	"Greater than or equal to" and "less than or equal to" tests.	SELECT * FROM employees WHERE salary >= 2500; SELECT * FROM employees WHERE salary <= 2500;
ANY SOME	Compares a value to each value in a list or returned by a query. Must be preceded by =, !=, >, <, <=, >=. Evaluates to FALSE if the query returns no rows.	SELECT * FROM employees WHERE salary = ANY (SELECT salary FROM employees WHERE department_id = 30);
ALL	Compares a value to every value in a list or returned by a query. Must be preceded by =, !=, >, <, <=, >=. Evaluates to TRUE if the query returns no rows.	SELECT * FROM employees WHERE salary >= ALL ( 1400, 3000);

Simple Comparison Conditions

A simple comparison condition specifies a comparison with expressions or subquery results.

simple_comparison_condition::=

Text description of simple_comparison_condition

expression_list::=

Text description of expression_list

If you use the lower form of this condition (with multiple expressions to the left of the operator), then you must use the lower form of the expression_list, and the values returned by the subquery must match in number and datatype the expressions in expression_list.

See Also: "Expression Lists" for more information about combining expressions SELECT for information about subqueries

Group Comparison Conditions

A group comparison condition specifies a comparison with any or all members in a list or subquery.

group_comparison_condition::=

Text description of group_comparison_condition

expression_list::=

Text description of expression_list

If you use the upper form of this condition (with a single expression to the left of the operator), then you must use the upper form of expression_list. If you use the lower form of this condition (with multiple expressions to the left of the operator), then you must use the lower form of expression_list, and the expressions in each expression_list must match in number and datatype the expressions to the left of the operator.

See Also: "Expression Lists" SELECT