Formatting SQL Parentheses: Boolean Logic Precedence and Readability

By Sharon Ben-Moshe · October 12, 2026 · 1 min read

Sharon Ben-Moshe is the founder of sqlfmt, a browser-based SQL formatter and validator with misspelled-keyword suggestions across PostgreSQL, MySQL, SQLite, SQL Server, and BigQuery.

Format complex parentheses and boolean logic in SQL WHERE clauses. Prevent AND/OR operator precedence bugs with clear visual indentation.

Quick answer

In SQL boolean logic, the AND operator has higher operator precedence than OR (AND binds tighter, like multiplication over addition). To prevent critical query logic bugs and maintain readability, format every compound OR expression inside explicit, indented parentheses with opening and closing parentheses aligned vertically.

FAQs

Why does 'A OR B AND C' produce unexpected results?

Because AND takes precedence over OR, the expression evaluates as `A OR (B AND C)`. If a developer intended `(A OR B) AND C`, rows matching A will be returned regardless of whether C is true, exposing sensitive or unverified records.

How should nested parentheses be indented in SQL?

Place the opening parenthesis at the end of the clause or on a new line, indent the enclosed expressions by 2 spaces, and place the closing parenthesis on its own line matching the indentation of the initiating clause.

Does adding redundant parentheses harm query performance?

No. The SQL optimizer builds an abstract syntax tree and evaluates logical truth conditions; parentheses clarify parsing and have zero performance penalty.

How does NOT interact with AND and OR?

The NOT operator has the highest precedence of the three (`NOT > AND > OR`). Always wrap negated compound expressions in explicit parentheses: `NOT (status = 'closed' OR status = 'archived')`.

SQL Formatting