T-SQL Validator — Check SQL Server Syntax Online

T-SQL-Specific Validation

When the dialect is set to T-SQL, the validator applies these additional checks:

• LIMIT — Flagged as invalid. SQL Server uses TOP N for simple row limiting or OFFSET...FETCH NEXT for pagination.
• :: cast operator — Flagged as invalid. SQL Server uses CAST() or CONVERT().
• ILIKE — Flagged as unsupported. SQL Server uses LIKE (which is case-insensitive by default with most collations).
• Standard checks — Unbalanced parentheses, unterminated strings, JOIN without ON, dangerous DELETE/UPDATE without WHERE.

Common T-SQL Mistakes

• Using LIMIT instead of TOP — Developers coming from MySQL or PostgreSQL often write LIMIT 10. SQL Server requires SELECT TOP 10 or OFFSET 0 ROWS FETCH NEXT 10 ROWS ONLY.
• String concatenation with + — T-SQL uses + for string concatenation, but if either operand is NULL, the result is NULL. Use CONCAT() or ISNULL() for safety.
• Division by zero — SQL Server raises an error on division by zero unless SET ANSI_WARNINGS OFF or NULLIF() is used to handle the zero denominator.
• Missing semicolons before CTEs — A WITH clause must follow a semicolon or be the first statement in the batch. The most common error is forgetting the semicolon: ;WITH cte AS (...).

T-SQL Features

SQL Server supports many features that are not available in other databases. The validator recognizes these as valid in T-SQL mode:

• TOP (N) WITH TIES for row limiting
• CROSS APPLY and OUTER APPLY for lateral joins
• PIVOT and UNPIVOT operators
• MERGE for upsert operations
• OUTPUT clause on INSERT, UPDATE, DELETE
• Table variables (DECLARE @t TABLE (...))