
SQL Experts in Dortmund
to turn data into reliable systems, matched in minutes with AIHire experts who design robust data models, tune complex queries and build reliable reporting pipelines with PostgreSQL, MySQL or Microsoft SQL Server. FRATCH connects you with vetted, available freelancers through fast, precise AI matching.
Meet FRATCH Experts in Dortmund, who have recently used SQL
Dany-Armand D.
Last position:
Senior Data Scientist at ibg NDT GmbH
- Investigate the relationship between Eddy Current Testing (ECT) signals and microstructural properties
- Detect latent patterns in ECT data that reflect intrinsic material characteristics
- Develop and validate predictive models for microstructural classification and quantification, using hardness and case depth as benchmarks
- Apply Bayesian Structural Equation Modeling for advanced data analysis
Christian F.
Last position:
Project Lead & Cyber Security Consultant at Deutsche Börse Gruppe
- Established a cyber resilience framework for AI-accelerated threats in the Frontier AI Threat Endurance (FATE) program: capability assessments, maturity assessments and gap analyses covering cyber security, operational resilience, incident response, recovery and governance, followed by target concepts and improvement measures
- Supported action owners from specification through implementation: implementation roadmaps, decision papers, management presentations and governance reporting, as well as audit- and supervision-ready documentation; managed stakeholders from IT, Information Security, Risk Management, Operational Resilience, Business Continuity and the business units
Yasin Y.
Last position:
Enterprise Architect at Bundesagentur für Arbeit
Task:
- Design and build a proof of concept (PoC) for a future-proof virtualization platform, taking secure system architectures into account
- Assess the current state of existing infrastructures and develop selection and evaluation criteria for the right OS virtualization platform
- Carry out the requirements analysis and then create and prioritize tickets in the ticket system
- Complete and continuously update a tool evaluation matrix based on PoC results
- Support team knowledge building through clear documentation of the approach and results in Confluence
- Enterprise analysis of existing hardware (creating different BoMs)
Technologies: Vmware, Vmware Aria Operations, Osism, Canonical OpenStack, FishOs, Linux, Terraform, Ansible, Confluence, Alma
Muhammad Y.
Last position:
SynQ × AutoStore
- Enterprise WMS customisation for Albert Heijn and EDEKA.
- Owned end-to-end test planning, automation, and performance validation for logistics automation software serving high-volume grocery warehouse operations.
Stephanie Z.
Last position:
Project Support / Project Coordination FTTx at Oliver Schulte Managementberatung
- Worked on an FTTx/telecommunications project within the project environment
- Supported operational project coordination and task follow-up
- Used Jira to create, process and track tasks and tickets
- Structured and maintained project-related information and work statuses
- Coordinated open points and ongoing tasks within the project team
- Supported the coordination of work packages and their processing status
- Followed up on tasks, feedback and open topics
- Worked at the interface between operational implementation and project organization
- Applied digital project management tools in the ongoing FTTx project
- Provided hands-on support with organizational and operational project tasks
Nemanja M.
Last position:
AI Engineer / Senior Backend Engineer at Intelycx
Manufacturing intelligence platform with enterprise workflows, RAG, real-time AI assistant features, and multi-repository backend architecture.
- Built and extended production AI/backend services with Django, DRF, FastAPI, GraphQL, Celery, PostgreSQL, MySQL, Redis, and WebSockets across a modular multi-repository platform.
- Contributed to ARIS V2, a real-time manufacturing AI assistant using LangChain, LangGraph, MCP tool orchestration, planning/execution flows, OpenAI, AWS Bedrock, Qdrant, and Elasticsearch/OpenSearch-backed retrieval.
- Supported rollout expansion from ARIS V1 in 4 of 17 client production plants to ARIS V2 currently active in 13 of 17 plants, increasing real-world deployment coverage to more than 50% of the client footprint.
- Worked on document-grounded RAG functionality including ingestion, OCR, chunking, embeddings, indexing, retrieval, reranking, and grounded answer generation for industrial workflows.
Stack: Python, Django, DRF, FastAPI, LangChain, LangGraph, GraphQL, Celery, WebSockets, OpenAI, AWS Bedrock, Qdrant, Elasticsearch/OpenSearch, PostgreSQL, MySQL, Redis, Docker.
Kersten L.
Last position:
Lead Architect / Lead Developer at Bettles: Sports Betting Platform
- Complete greenfield rebuild across the whole stack — built AI-native: backend in Go and NestJS, PostgreSQL (CNPG) on K3s with GitOps/Terraform; frontend on Angular 22, zoneless.
- Orchestrated coding agents (e.g. Claude Code, Cursor) across the entire lifecycle — architecture, implementation, testing, reviews, documentation — driven by Specification-Driven Development (SDD).
- “Bruno” — LLM commentator persona backed by RAG and MCP for a personality that stays consistent across all generations (match previews, post-match reports, his own virtual bets).
Angular 22 (zoneless, without Zone.js), Claude Code, Claude Code Skills, CNPG, Cursor, Design Tokens (Spec for Code), Docker, Gherkin, Git, GitLab, GitOps, Go, Google Gemini, Grafana, Hetzner Cloud, K3s, Keycloak, Kubernetes, Lighthouse, LLM Integration, Model Context Protocol (MCP), NestJS, Node.js, NPM, Playwright, PostgreSQL, Prometheus, RAG, REST, Specification-Driven Development (SDD), Structured Outputs, Terraform, TypeScript, Vitest
Volker D.
Last position:
Developer at DV-Consulting und Entwicklung Volker Döch
- Developed a new web app to manage and configure counting devices for large events
- Technologies: .NET 10, C#, Blazor, MudBlazor, MySQL, Git
Thomas G.
Last position:
Senior .NET / Cloud Engineer at Freelance
Building an observability and alerting solution for Business Central Job Queue Monitoring
- Built a central monitoring solution to monitor the Business Central Job Queue in a multi-organization environment in Azure DevOps
- Integrated Azure Application Insights and Log Analytics for the structured collection and analysis of job runtimes and error events
- Developed KQL queries for targeted analysis of failed jobs and detection of error patterns
- Connected Grafana and Power BI to visualize operational metrics and job statuses in real time
- Implemented an automated alerting workflow with Power Automate – an email notification is triggered immediately when a job fails
- Ensured transparency into the status of productive background processes during ongoing operations
Result: Full transparency into failed Business Central jobs · Significant reduction in response time through automated email alerting · Stable foundation for the proactive operation of productive background processes
Technologies: Azure DevOps | Application Insights | Log Analytics | KQL | Grafana | Power Automate | Power BI | Business Central | Azure Monitor
Adnan U.
Last position:
Independent AI & Automation Projects
- Development of an automated job-scouting workflow for the aggregation and LLM-based evaluation of job postings from RSS feeds and APIs.
- Development of a Telegram bot for voice and text messages, featuring LLM-supported processing, summarization, and structured JSON output.
- Implementation of a personal task-planning assistant using n8n, OpenRouter, and Supabase for automated daily and knowledge organization.
- Development of LLM chatbots for structured knowledge retrieval utilizing prompt constraints, guardrails, and forced output formats.
Rainer P.
Last position:
Senior Controller at Stahlhandel-Servicecenter Bönen
- Controlling project work: introduction of customer quotation costing and development of a trading/forward costing model for sales
- Development of a manufacturing cost calculator
- Theoretical design and practical implementation: interim Excel version introduced at short notice; migration to INFOR LN and preparation of the requirements specification
- Most of the project management using modern tools (Loop, Jira, Excel, PowerPoint)
- Regular reporting on submitted quotations (db1 and full-cost coverage) and comparison with post-calculation
Manuel K.
Last position:
.NET Developer, SAP Business One Consultant at Own Projects
- DTO class generator: In-house development of a tool for the automatic generation of classes, functions, and methods for use in .NET Core projects based on SAP Business One Service Layer metadata
- E-invoice import add-on: Development of a SAP Business One add-on / coresuite module for the automated import of ZUGFeRD e-invoices as incoming invoices – with configurable mapping to flexibly control the import logic across four mapping types (DIRECT, SQL, FIXED, EXPR). The add-on is available as a licensed product for SAP Business One customers.
Stack: SAP Business One, SAP Business One Service Layer, coresuite Country Package, C#
Arkadius S.
Last position:
AWS Pricing Platform / API & Integration Architecture at Porsche Digital
Development and evolutionary further development of a highly available, cloud-native microservice and integration architecture for dealer and retail processes in the Porsche Car Configurator.
Responsibilities
- Development of Java-/Kotlin-based backend, API, and integration components (Spring Boot)
- Integration of internal and external systems via REST/OpenAPI, GraphQL, Apache Kafka, and AWS SQS (synchronous and asynchronous)
- Implementation of stable, high-performance communication and data flows in a cloud-native platform architecture
- Processing of structured data formats (JSON, Protobuf, GraphQL schemas) based on existing API patterns
- Performance optimization of distributed microservices with reduced response times and higher operational stability
- Technical tests (unit, integration, and API tests) as well as error analysis in production-like environments
- AWS Infrastructure as Code with Terraform and AWS CDK
- CI/CD automation (build, test, and deployment pipelines) with GitHub Actions
- AI-supported feature implementation (GitHub Copilot Agent)
Label: Kotlin, Java 25, Spring Boot 4, Protobuf, TypeScript, AWS, Terraform, CDK, Apache Kafka, AWS SQS, REST/OpenAPI, GraphQL, JSON, PostgreSQL, Docker, GitHub Actions, Maven, Gradle, JUnit, Mockito, Testcontainers
Patrik G.
Last position:
Technical Lead Conversational AI at CANCOM
- Technical lead of a team developing agentic chatbot solutions (React, TypeScript, Python, FastAPI)
- Architecture design for multi-LLM dialog systems - focus on maintainability, UX, and autonomous execution
- Stakeholder alignment, CI/CD processes, and AI integration at enterprise level
Diego E.
Last position:
RPG Software Developer from RPG III to Free Format
- Development of software and system support for RPG development.
- Development, optimization and maintenance of programs in RPG (RPG II to ILE Free Format).
- Performing integration tasks, data management as well as applying and managing system updates.
- User support and training to ensure smooth system operation.
Discover over 15,000 top freelancers
Statistics of experts using SQL
Aggregated from the professional profiles of matched freelancers.
Experience
21 years (Germany: 19 years)

Position duration
2.1 years (Germany: 5.1 years)

Positions per freelancer
14 (Germany: 12)

Top business areas
Information Technology, Product Development, Project Management

Top industries
Information Technology, Banking and Finance, Manufacturing

Certification focus areas
Information Technology, Quality Assurance, Product Development
Bachelor's degree or higher
86% (Germany: 90%)
Master's degree or higher
59% (Germany: 61%)
Doctorate
10% (Germany: 9%)

Certifications per freelancer
3

Most common languages
German, English, Spanish

Speak two or more languages
100% (Germany: 97%)
Based on our profile pool as of 29 Oct 2026.
Daily rate distribution
The chart shows how the daily rates of experts in this technology in Dortmund are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows the share of experts charging within that range.
Average rates of experts in Dortmund using SQL
Rates are based on recent contracts and do not include FRATCH margin.
The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.
The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.
Calculated based on our freelancers’ daily rates as of 29 Oct 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
SQL experts industry focus
See which industries our matched freelancers work in most often — every figure is calculated live from the freelancers on FRATCH.
- Information Technology (81%)
- Banking and Finance (49%)
- Manufacturing (49%)
- Retail (49%)
- Healthcare (41%)
- Education (38%)
- Professional Services (38%)
- Insurance (32%)
Please note that freelancers can work across multiple industries, so percentages overlap.
About the technology
SQL foundations
SQL, or Structured Query Language, is the standard way to work with data in relational databases. It lets teams define tables, connect related records, query information, and control how data is inserted or changed. SQL sits behind applications, reporting tools, finance systems, customer platforms and operational workflows.
Databases and tooling
SQL specialists work across database engines and the tools around them. Common environments include PostgreSQL, MySQL, MariaDB, Microsoft SQL Server, Oracle Database and cloud services such as Amazon RDS, Azure SQL and BigQuery. Their work may also involve Git, migration tools, dbt, BI software and automated test pipelines.
Typical deliverables
- Relational data models with clear keys, constraints and relationships
- Queries, views, stored procedures and functions for business processes
- ETL or ELT pipelines that move and prepare data for analysis
- Dashboards, reporting datasets and controlled access for teams
- Database migrations with rollback plans and validation
A strong SQL professional connects database design with the application or reporting layer. They document assumptions and make changes reproducible across development, testing and production.
When to hire specialists
Companies bring in freelance SQL expertise when reports are slow, data is inconsistent, or an existing schema no longer supports the product. Specialists can also help during a migration, a warehouse implementation, a merger of data sources or a temporary capacity gap. In Dortmund, they may support local industrial, logistics, retail and service organizations while collaborating remotely with distributed teams.
Quality signals
Good SQL work is readable, testable and safe to operate. Experienced professionals inspect execution plans, choose suitable indexes, handle null values deliberately and consider transactions, locking, permissions and recovery. They ask how data is created and used before changing the schema, rather than optimizing a query in isolation.
Collaboration and outcomes
Freelance SQL specialists often work alongside application teams, data analysts, product professionals and infrastructure specialists. Clear acceptance criteria, sample data and access to relevant documentation make remote or on-site collaboration effective. The best outcome is not only a faster query, but dependable data that people can trust across daily operations and strategic decisions.
Frequently asked questions
Curious about SQL? Here are the answers that come up again and again.
SQL is used to store, retrieve, update and organize structured data in relational databases. Companies rely on it for application backends, reporting, analytics, financial records, inventory, customer data and operational workflows.
SQL databases use structured schemas, relationships and a query language designed for relational data. NoSQL systems can be more flexible for document, key-value, graph or high-volume distributed workloads, so the right choice depends on data shape, consistency needs and access patterns.
A capable SQL specialist may work with PostgreSQL, MySQL, MariaDB, Microsoft SQL Server or Oracle Database. The important skill is understanding relational principles while adapting to each system’s syntax, indexing behavior, transaction model and operational tools.
Strong SQL work often connects with data modeling, database administration, ETL or ELT, cloud infrastructure and business intelligence. Familiarity with Python, application frameworks, dbt, Git and observability tools can also improve delivery when database work is part of a wider data system.
The right SQL experience depends on the scope and risk of the work. A straightforward report may need focused query and data-modeling skills, while a migration, performance investigation or production redesign calls for someone who can assess dependencies, recovery, security and operational impact.
Yes, SQL projects are often well suited to remote collaboration when access, documentation and data-handling rules are clear. Dortmund teams may still prefer on-site sessions for discovery or sensitive systems, while regular communication in German or English can support distributed work.
Review how the SQL specialist explains data relationships, edge cases, execution plans and failure handling. Ask for examples of readable queries, safe migrations, testing practices and measurable improvements without exposing confidential customer data.
Before using Structured Query Language, clarify the database engine, data volume, environments, access permissions, delivery expectations and definition of success. It is also important to understand whether the work affects live transactions, compliance obligations, reporting accuracy or downstream applications.
The average hourly rate of freelancers in Dortmund, Germany who have used SQL in their recent projects is 92 €, which corresponds to a daily rate of about 732 € based on an 8-hour working day.
Of the freelancers in Dortmund, Germany who have used SQL in their recent projects, 86% hold at least a Bachelor's degree, 59% hold at least a Master's degree, and 10% hold a doctorate.
On average, freelancers in Dortmund, Germany who have used SQL in their recent projects have 21 years of professional experience, with a single engagement typically lasting around 2.1 years.
The most common languages among freelancers in Dortmund, Germany who have used SQL in their recent projects are German (100%), English (100%), and Spanish (19%).
The most common industries among freelancers in Dortmund, Germany who have used SQL in their recent projects are Information Technology (81%), Banking and Finance (49%), and Manufacturing (49%).
The most common business areas among freelancers in Dortmund, Germany who have used SQL in their recent projects are Information Technology (86%), Product Development (73%), and Project Management (65%).
Main locations of FRATCH Experts, who have recently used SQL
Our freelancers and interim experts are at home across the DACH region — available on-site in the major business hubs or fully remote. Choose a location to discover matched specialists, local market insights and up-to-date availability.
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