SQL operators are symbols and keywords that perform operations on their arguments.
Types of Operators
The following types of operators are available in SQL:
Arithmetic operators such as + and - operate on numeric, DateTime, and Interval data
The concatenation operator || operates on character and byte types.
Comparison operators such as = and > test the truth of relations between their arguments.
For information on comparison operator, see Chapter 10: “Comparison Operators and Functions.”
Because comparison operators are a type of logical predicate, see Chapter 20: “Logical Predicates.” Comparison operators are also known as conditional expressions because they result
in a value of TRUE, FALSE, or unknown (NULL).
Set operators, or relational operators, such as INTERSECT and UNION combine result
sets from multiple sources into a single result set.