The comparison predicate is used to compare two values. The left hand side operand has to be a value expression whereas the right hand sight operand can additionally be a dynamic parameter specification or a scalar sub-query.
Syntax
<comparison predicate> ::= <value expression> <comparison operator> ( <value expression> | <dynamic parameter specification> | <scalar subquery> ). <comparison operator> ::= '<' | '=' | '>' | '<=' | '<>' | '>='.
The data types of the two <value expression>s in the <comparison predicate> must be comparable.
If either of the <value expression>s is NULL, the result of the <comparison predicate> is unknown.
Note
It is not possible to test for NULL values with a comparison predicate. You may wish to use a null predicate instead.
More information about comparable types: Open SQL Data Types
Syntax
SELECT * FROM a WHERE c > 0
Comparison predicate. This SELECT yields all rows from table a where the column a.c has a value larger than 0.
Syntax
DELETE FROM employees WHERE employee_id = ?
Dynamic Parameter in Comparison Predicate. All employees with the employee_id equal to a given parameter are delete from the table employees.