Operator precedence determines the order in which SQL evaluates operators in an expression. Logical conditions involving NOT, AND, and OR can produce different results depending on evaluation order.
Understanding precedence prevents incorrect filtering when multiple logical conditions are combined.
A query containing AND and OR may return unexpected records if the intended logic is not grouped correctly.
SELECT
EmployeeName,
Department,
Salary
FROM Employees
WHERE Department = 'IT'
OR Department = 'Finance'
AND Salary > 60000;Operator precedence is important in customer segmentation, compliance rules, financial filters, and complex business logic.
- SQL evaluates operators according to precedence rules.
- AND generally has higher precedence than OR.
- NOT has higher logical precedence.
- Parentheses can explicitly control evaluation.
- Clear grouping reduces logical errors.
Why is operator precedence important?
It determines how SQL evaluates multiple conditions and therefore affects which rows are returned.
How can you control condition evaluation?
Use parentheses to explicitly group conditions and make the intended logic clear.