How to Fix CodeQL Query Execution Error

In this tutorial, you'll learn about How to Fix CodeQL Query Execution Error. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

CodeQL query fails with Error: Query compilation failed or No codeql database found at path — the QL query has syntax errors or the CodeQL database does not exist at the specified location.

The Problem

$ codeql database analyze my-db queries/my-query.ql
Error: No CodeQL database found at my-db

Step-by-Step Fix

Step 1: Create a CodeQL database

codeql database create my-db --language=javascript \
  --source-root=/path/to/project

Step 2: List available queries

codeql query list

Step 3: Run a built-in query suite

codeql database analyze my-db \
  codeql/javascript-queries:codeql-suites/javascript-security-extended.qls \
  --format=sarif-latest --output=results.sarif

Step 4: Run a custom query

/**
 * @name JavaScript alert
 * @kind problem
 * @id js/example/alert
 */
import javascript

from AlertExpr a
select a, "This code contains an alert statement."

codeql database analyze my-db my-query.ql

Step 5: Upgrade database format

codeql database upgrade my-db

Step 6: Run with resource limits

codeql database analyze my-db queries.qls \
  --ram=4096 --threads=4 --timeout=600

Prevention Tips

• Always use codeql database create before analyzing
• Keep CodeQL database and CLI versions compatible
• Use query suites (.qls) instead of single queries
• Run with adequate memory for large codebases

Common Mistakes with query error

1. Mixing let bindings with <- bindings in do notation, producing type errors
2. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors
3. Non-exhaustive pattern matches that compile with warnings then crash at runtime

These mistakes appear frequently in real-world CODEQL code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

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