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.
Operator Category | Notation | Meaning |
---|---|---|
Assignment |
:= | Store the value |
Arithmetic |
+
- / * ** |
Addition
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 |
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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