SQLChecker

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SQL Syntax Check, Format, and Tuning All-in-One

SearchCode Pro's "AI SQL Checker" is an integrated review tool for engineers that goes beyond simple syntax error detection. It offers an **SQL Formatter** to enhance readability and provides **Performance Tuning** suggestions to improve query speed.

Full Support for Major Database Dialects

SQL syntax differs slightly between database products (dialects). Our tool also performs dialect checks, and the AI appropriately reviews by understanding the characteristics of each.

Specific SQL Error Cases Solved by AI

Shorten the time spent searching for the mistake when "Syntax Error" appears in the console. The AI instantly finds the following mistakes that beginners often fall into.

1. Full-width Space / Invisible Character Contamination

A full-width space that looks like a blank space in the editor can cause an error during SQL execution. Our checker automatically detects these "invisible errors" and suggests deletion.

2. Mismatched Parentheses and Comma Errors

Points out errors easily missed by eye, such as forgetting closing parentheses in nested subqueries or having an unnecessary trailing comma in the SELECT clause.

3. Missing GROUP BY Specification

Prevents errors that occur when using aggregate functions (COUNT, SUM, MAX, etc.) by checking that all non-aggregated columns are included in the GROUP BY clause.

4. N+1 Issues and Inefficient Join Warnings

For practices that are syntactically correct but severely degrade performance (like non-indexed LIKE searches or unnecessary DISTINCT usage), the tool provides suggested improvements (best practices).

5. 🛡️ SQL Injection Vulnerability Diagnosis

Automatically checks for dangerous practices (like direct string concatenation of user input) that could lead to SQL Injection. It points out vulnerabilities and suggests secure correction examples using placeholders (Prepared Statements).

Common SQL Syntax Errors and Causes

When SQL doesn't work, the cause is often a simple syntax error. Here are common errors frequently encountered by beginners and their solutions.

1. Missing or Extra Commas

A mistake where a comma is left after the last column name in a SELECT clause, or conversely, forgotten entirely.

-- Mistake (Comma at the end)
        SELECT id, name, email, FROM users;

        -- Correct
        SELECT id, name, email FROM users;

2. GROUP BY Specification Error

When using aggregate functions like COUNT or SUM, all columns specified in SELECT (other than the aggregate function) must be included in GROUP BY.

3. Full-width Space Contamination

The code may contain full-width spaces which are invisible but cause errors. Our SQL checker can instantly detect these "invisible errors."

4. Use of Reserved Words

Using words already defined in SQL (reserved words) like ORDER or USER as table or column names can cause errors. In such cases, they must be enclosed in backticks, like `user`.