    Operators are symbols and keywords that specify an operation to be performed on one or more value expressions.

### Arithmetic operators

The arithmetic operators perform operations on numeric values.

 Operator Symbol Operation + Addition - Subtraction * Multiplication / Division

Note: The addition (+) and subtraction (-) operators are also used in arithmetic operations on datetime values.

### Concatenation operators

The concatenation operator is used to concatenate string values.

 Operator Symbol Operation || String concatenation

Note: The arithmetic addition (+) operator can be used as an alternate string concatenation operator.

### Comparison operators

The comparison operators are used in some predicates to specify comparison tests.

 Operator Symbol Operation = Equal to <> Not equal to < Less than > Greater than <= Less than or equal to >= Greater than or equal to

Note: The equals sign (=) is also used as an assignment operator.

### Boolean operators

The boolean operators are used to combine predicates in search conditions.

 Operator Keyword Operation NOT Invert the result of the boolean test AND Test if both predicates are TRUE OR Test if either of the predicates is TRUE

Note: Check the truth tables to see how combined boolean expressions are evaluated.

### Assignment operator

The equals sign is used for value assignments.

 Operator Symbol Operation = Value assignment

### Operator precedence

Operator precedence determines the order in which operations are performed during the execution of a complex value expression with multiple operators.

Operators are evaluated in the following order, ranked from highest to lowest precedence level:

 ♦ * (multiplication), / (division)
 ♦ ||, + (concatenation)
 ♦ =, <>, <, >, <=, >= (comparison operators)
 ♦ NOT
 ♦ AND
 ♦ OR

Operators on the same precedence level are evaluated left to right based on their position in the value expression.

If a value expression has nested parentheses, the innermost expression is evaluated first.

Tip: Instead of relying on the defined operator precedence, it is recommended to use parentheses to explicitly specify the order of operations in complex value expressions with many operators. All operations inside parentheses are evaluated first to yield a single value before that value is used as an operand in other operations.

### Conformance

 SQL:2003 standard NexusDB extensions - - Core SQL Plus sign as string concatenation operator 