About

Code readability remains a primary factor in software maintainability. Database queries often become convoluted strings of text during application logging or rapid prototyping, making debugging a strenuous task. This tool parses raw Structured Query Language strings and reconstructs them into a structured format. It applies deterministic rules for indentation and capitalization, transforming a single-line blob into a vertically aligned script. This process aids developers in visualizing the logical flow of data retrieval operations, join conditions, and nested subqueries. The parser operates entirely within the browser client, ensuring that sensitive schema information or data values are never transmitted to external servers. Correct formatting reduces cognitive load when reviewing legacy code or optimizing query performance plans.

Formulas

The formatting engine conceptualizes the SQL string as a stream of tokens, categorized into specific sets for processing. Let T be the set of all valid tokens in the input string.

IndentLevel(t_i) = IndentLevel(t_i-1) + Delta(t_i)

Where Delta is determined by the token type. If t ∈ OPEN_BLOCK (e.g., (, CASE), the indentation increments. If t ∈ CLOSE_BLOCK (e.g., ), END), it decrements. The readability score R is optimized by minimizing line length L while maximizing vertical alignment.

Format(Query) = n∑i=0 ( Indent(d_i) ⋅ Token_i + Newline_i )

Here, d represents the depth of the Abstract Syntax Tree (AST) node at index i.

Reference Data

SQL Category	Keyword Examples	Standard Formatting Behavior
Data Query (DQL)	SELECT, FROM, WHERE	Starts a new line. Resets indentation level to base. acts as a primary block anchor.
Data Manipulation (DML)	INSERT, UPDATE, DELETE	Primary statement headers. often followed by INTO or SET on subsequent lines.
Joins & Relations	LEFT JOIN, INNER JOIN, ON	Indented relative to the FROM clause. conditions break to new lines for readability.
Logic Control	CASE, WHEN, THEN, ELSE	Triggers a nested indentation scope. END closes the scope and reduces indentation.
Set Operations	UNION, INTERSECT, EXCEPT	Treated as top-level separators between distinct query blocks. often surrounded by blank lines.
Grouping & Ordering	GROUP BY, ORDER BY, HAVING	Follows the WHERE clause hierarchy. typically aligns with the primary query keywords.
Data Definition (DDL)	CREATE, ALTER, DROP, TRUNCATE	Statement starters. column definitions inside (parentheses) are indented.
Transaction Control	COMMIT, ROLLBACK, SAVEPOINT	Standalone commands. usually zero indentation unless inside a stored procedure block.

Frequently Asked Questions

No, this is a formatter, not a validator. It tokenizes the input based on standard SQL patterns and rearranges whitespace and capitalization. If your query contains syntax errors (like missing commas or misspelled table names), the tool will still attempt to format it, potentially making the error easier to spot, but it will not flag invalid code.

No. The processing engine is written entirely in JavaScript and executes locally within your browser. No data leaves your device, ensuring that proprietary schema structures, table names, and sensitive values in `WHERE` clauses remain private.

The formatter detects opening and closing parentheses `()` and keywords like `EXISTS` or `IN`. When a subquery begins, the indentation level increases. This creates a visual hierarchy where the inner query is shifted to the right, clearly distinguishing it from the outer parent query.

Inline comments (starting with `--` or `#`) are generally preserved at the end of the line or moved to the preceding line depending on the context. Block comments (`/* ... */`) are treated as atomic tokens. Complex interleaving of comments within keywords may occasionally result in displacement to maintain the structural integrity of the code block.

The tool uses a generalized SQL grammar that covers the intersection of ANSI SQL, MySQL, PostgreSQL, and SQL Server (T-SQL). While it handles the vast majority of standard keywords and control structures correctly, highly specific dialect features (like obscure stored procedure syntax) might not be highlighted as reserved words but will still be formatted structurally.