Operator precedence

Operators in an expression are evaluated left-to-right in the order of their precedence. The following table lists the operators and their precedence:

PL/MX operator precedence
Operator Meaning Order of precedence
Unary +, Unary - Arithmetic Identity, Arithmetic Negation 1
*, / Multiplication, Division 2
Binary +, Binary -, || Addition, Subtraction, Concatenation 3
=, <, <=, >, >=, ^=,!=, <>,~=, IS NULL Comparison 4
NOT Logical Negation 5
AND Logical Conjunction 6
OR Logical Disjunction 7

To alter the order of evaluation, use parentheses. The most deeply nested expressions in parentheses are evaluated first, then operator precedence is used, and, finally, left-to-right order.