What Is a SQL Validator?
A SQL Validator is a static code analysis tool that parses SQL queries, DDL schemas, and DML data manipulation scripts locally before executing them against a database. It inspects SQL syntax, verifies clause ordering (such as SELECT, FROM, JOIN, WHERE, GROUP BY), detects dangerous statements (like UPDATE or DELETE missing a WHERE clause), and identifies common SQL mistakes.
SQL Syntax Validation vs Live Database Execution
Static SQL validation verifies language grammar and syntax correctness without connecting to a live database engine. While it detects missing parentheses, invalid keywords, and malformed clauses, it cannot verify:
- Whether referenced tables or columns actually exist in your database instance.
- Database user permissions or execution roles.
- Database-specific runtime constraints or live data state.
Understanding Common SQL Validation Warnings & Errors
UPDATE / DELETE Without WHERE
Executing an UPDATE or DELETE statement without a WHERE clause will modify or delete every single row in the table. The validator flags this with a prominent WARNING.
NULL Comparison Mistakes
In standard SQL, comparing columns using col = NULL or col != NULL evaluates to UNKNOWN. SQL requires IS NULL or IS NOT NULL expressions.
Syntax & Unclosed Strings
Catches missing quotes, unterminated multi-line comments, missing parentheses in subqueries or CTEs, and keyword order violations.
Supported SQL Dialects
SQL syntax varies slightly across database engines. Our validator provides dialect-specific lexing rules for Generic SQL, MySQL, PostgreSQL, SQLite, SQL Server (T-SQL), and Oracle.
Frequently Asked Questions (FAQ)
Is my SQL code sent to any cloud server or database?
No. Static analysis and syntax parsing occur 100% locally within your client browser using JavaScript memory. Your SQL scripts are never uploaded or executed against a database.
How is SQL Validator different from SQL Compare?
SQL Validator parses syntax correctness, DDL/DML rules, and safety linter warnings. SQL Compare compares two different SQL schema scripts side-by-side to highlight added or modified columns.
Why does the tool warn about UPDATE without WHERE?
An UPDATE statement without a WHERE clause will modify every row in the target table. The validator flags this as a safety warning to prevent accidental database data overwrites.