### 2.5. Common Operators

An operator is a symbol or keyword that the language provides to perform an arithmetic, logical, or other function. As in mathematics, the "things" upon which the operators operate are called operands. This section explores some of the most frequently used operators in the PL/SQL language; they are summarized in Table 2-1. If you already know one programming language, you'll be happy to hear that most of PL/SQL's operators, such as mathematical and comparison operators, are consistent with common programming usage.

Table 2-1. Common PL/SQL operators
Operator Category Notation Meaning
Assignment
`:=`
Store the value
Arithmetic +

-

/

*

**

Subtraction

Division

Multiplication

Exponentiation
Logical AND

OR

NOT
Conjunction

Disjunction

Negation
Comparison (of non-nulls) =

!=

<

>

<=

>=

IN

BETWEEN
Equality

Inequality

Less than

Greater than

Less than or equal

Greater than or equal

Equality disjunction

Range test
Comparison (of nulls) IS NULL IS NOT NULL Nullity test Non-nullity test
String LIKE || Wildcard matching Concatenation

#### 2.5.1. Assignment Operator

The assignment operator, which in notation consists of a colon followed immediately by an equals sign, is a way to copy data from one place to another. Given two variables a and b, an assignment statement is of the following form:

`a := b;`

which copies the contents of the variable b into the variable a.

The righthand side may consist of literal values, the result of a function call, ...

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