SQL Experts in Dusseldorf
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Meet FRATCH Experts in Dusseldorf, who have recently used SQL
Alwin G.
Last position:
IT Interim Manager & AI Strategist
- AI product development: Design of an AI-supported GRC platform to automate compliance processes.
- AI expertise: Strategic deepening in Agentic AI and GenAI as a core asset for modern IT governance
- IT interim management and strategic consulting
Rudolf Eggelbusch
Last position:
Datacenter Engineer, Network & Security Administrator at International insurance group
Operation and further development of the network and security infrastructure.
Monitoring, analysis and resolution of network and security incidents.
Cross-department collaboration with other specialist teams for operations, further development and reporting.
Firewall vulnerability analysis.
Firewall rule approvals.
Troubleshooting IP communication issues in the network and firewall infrastructure.
Security-critical IT infrastructure, processing of personal data, compliance with legal regulations.
Products: Palo Alto Networks Firewalls, Cisco ACI, Checkpoint Firewalls, F5
Technologies: SDN, SDWAN, Cisco EPIC, Cisco ACI
Boris Solos
Last position:
Generalist expert for software development at Mercor
- Training the AI models, evaluating images and texts for UI/UX, turning the provided data into insights via OpenAI Feather as part of the machine learning workflow
Technologies: OpenAI Feather
Marc Smyk
Last position:
Fullstack Developer at PLANT-MY-TREE
PLANT-MY-TREE®-per-order
The application enables Shopify merchants to automatically place tree-planting orders for every incoming order. By integrating ecological contributions directly into the purchase process, the manual effort for tracking and billing reforestation initiatives is eliminated. The system increases transparency for end customers through real-time visualizations of the ecological impact directly in the storefront. The architecture is based on a modular monolith with Spring Boot in the backend and an integrated React app inside the Shopify admin area. The solution uses webhooks to capture order data in an event-driven way and integrates the weclapp ERP system for automated monthly invoicing. An app proxy mechanism provides dynamic statistics such as CO2 compensation and planted trees without any performance loss for the merchant shop.
Tasks:
- Design of the modular software architecture based on Spring Modulith to ensure high maintainability
- Development of the event-driven business logic for evaluating Shopify orders via webhooks
- Implementation of automated invoicing by connecting the weclapp REST API
- Building the frontend using React Router and Shopify App Bridge for native integration
- Design of the database model and implementation of the persistence layer with JPA/Hibernate and Prisma
- Integration of internationalization processes for global use in the frontend and email communication
- Automation of deployment processes using Docker and GitLab CI/CD
Project skills: Java 25, Spring Boot, Spring Security, Spring Modulith, Hibernate, JPA, REST API, PostgreSQL, Maven, Liquibase, React, TypeScript, React Router, Vite, Node.js, Prisma, Zod, Docker, Docker Compose, GitLab CI/CD, Shopify CLI, Shopify App Bridge, Polaris, weclapp, i18next, Lombok, Vitest
Christian Wonneberger
Last position:
Software Engineer, cross-platform Application Manager at International major bank
- Creating interfaces between the legacy platform and the new container solution
- Coordinating required contributions from line units
- Moderating regular status meetings with the software vendor
- Minimally invasive conversion of TWS scheduling from the old to the new platform
- Environment: IBM Mainframe, DB2, CICS, MQ, Red Hat Linux, Oracle, Kubernetes, Kafka, Helm, GitLab, Jenkins
Ludo Prokop
Last position:
Senior Consultant at Insurance
- DWH modernization
- Migration from Informatica PowerCenter to IDMC/CDI
- Migration from IBM DB2 to Databricks
Technologies: Informatica IDMC, Databricks
Archana Ravikumar
Last position:
Power BI Assistant at Cataliquent Projekt GmbH
- Evaluate, design, and implement Power BI solutions for Cat4 reporting, significantly improving reporting efficiency, accuracy, and stakeholder visibility.
- Develop and maintain robust data integration interfaces between Cat4 and Power BI, eliminating manual processing bottlenecks.
- Configure and continuously optimise Power BI reports to deliver sharper management insights and support data-driven decision-making.
- Ensure full GDPR data protection compliance across Power BI reports, proactively identifying and mitigating risks.
- Acquired in-depth product knowledge of CAT4, a globally deployed enterprise platform, enabling effective requirements analysis, solution design, and seamless Power BI integration across client environments.
- Developed and integrated scalable reporting templates within the CAT4 product interface, delivering new product features and enhancing data visualisation, reporting efficiency, and stakeholder visibility across global users.
- Trained and mentored staff on Power BI configuration and best practices, accelerating adoption and embedding a data-driven culture.
- Prepared clear technical documentation and delivered hands-on demonstrations to end users and clients, ensuring smooth adoption and confident use of Power BI solutions integrated with CAT4.
- Researched and recommended licensing strategies for cost-effective and scalable Power BI deployment.
SKILLS - BI & Visualisation: Power BI (Desktop, Service, Report Builder), DAX, Power Query
Project and Product Management Tool: CAT4
Franziska Meyndt
Last position:
Business Insights & Analytics Working Student at Eurowings Holidays
- Built & maintained 10+ Power BI dashboards tracking booking, revenue & yield KPIs, reducing manual reporting effort
- Developed a centralized data model (SQL & Azure Analysis Services), integrating multiple data sources to improve reporting consistency & scalability
- Delivered ad-hoc analyses for leadership, supporting data-driven decision-making across multiple business units
Thorsten Lenzen
Last position:
Senior Security Analyst
- Analysis and remediation of security vulnerabilities in a risk assessment system for energy trading
- System analysis
- Threat modeling
- Decision-making on vulnerability mitigation strategies
- Implementation of vulnerability detection mechanisms
- Security scans
- DevSecOps practices
- Technical environment: Visual Studio Code, JetBrains Suite, MS Threat Modeling Tool, DevSecOps, Git, AWS, DynamoDB, SQL Server, Endur, Snowflake, Orca
- Languages: C#, JavaScript, TypeScript, Python, PowerShell, Bash, Terraform, SQL
Olga Methner
Last position:
Telefónica Deutschland Holding AG
- Implemented the BI solution and replaced the old BI landscape
- Led the “Sales Bonus Plan” subproject: expanded the existing solution and migrated to Azure (Databricks)
- Led the “Cognos Migration” subproject: expanded existing data warehouses based on MS technologies (source systems: Oracle), analyzed business requirements and designed the technical solution
- Expanded the relational DWH database
- Developed ETL processes using SSIS
- Developed the multidimensional database (OLAP Cubes/SSAS)
Alexander Rautzenberg
Last position:
Business Analyst at Financial Services Provider Landesbank
The Helaba ATLAS project aims to modernize core systems and make them future-proof. As part of the subproject, the existing legacy system for international payments is being replaced by a modern web-based application.
- Analysis of functional and technical requirements
- Analysis and optimization of business processes
- Process modeling
- Preparation and facilitation of workshops
- Defining project scope and prioritizing requirements
- Business process management (analysis, modeling, and optimization)
- Specification of user stories
- Designing business and authorization concepts
- Testing and acceptance
- Designing mockups in Figma
- Creating the UI/UX style guide for web applications Approach: Scrum (agile) Technologies: Jira, Confluence, MS Teams, Conceptboard, Java, Vaadin, Figma
Khattab Mennat
Last position:
Software Tester at Atlas Elektronik GmbH
- Deriving test cases in IBM DOORS for various devices according to ISTQB
- Automating and running test cases in Python under Linux
- MobaXtrem, Windchill are in use
Boban Stamenkovic
Last position:
Senior Citrix Consultant & Architect, NetScaler Expert at Freelancer
- Design, installation, configuration, administration, optimization, and further development of IT infrastructures in Citrix environments
- Upgrading older Citrix systems to the latest versions
- Installation, configuration, and delivery of applications in Citrix environments
- Support in 2nd- and 3rd-level support
- Performing performance analyses and optimizations in complex Citrix environments
- Analysis and fixing of issues in complex Citrix systems
- Creating, updating, and maintaining technical documentation
- Troubleshooting slow logons in Citrix XenApp / CVAD environments
- Analysis and fixing of printer problems in Citrix environments
- Creating, maintaining, and optimizing Citrix VDI policies
- Citrix Virtual Apps and Desktops (CVAD) 2402 LTSR, Citrix Virtual Desktop Infrastructure (VDI), Citrix Hypervisor / Citrix XenServer, Citrix Director / Citrix StoreFront, Citrix Machine Creation Services (MCS) / Citrix Provisioning Services (PVS), Citrix App Layering, Citrix Workspace Environment Management (WEM), Citrix Profile Management
- NetScaler SDX 14 / NetScaler Gateway 14 / NetScaler Console 14, NetScaler Load Balancing / Global Server Load Balancing (GSLB), NetScaler Applications Analytics (Web Insights, Security Insights, SSL Insights, TCP Insights, Gateway Insights, HDX Insights, ADC Infrastructure Analytics)
- Design, installation, configuration, management, optimization, and further development of IT infrastructures in Microsoft environments
- Upgrading older Microsoft systems to the latest versions
- Installation, configuration, and delivery of applications in Microsoft environments
- Creating, managing, and optimizing Microsoft Group Policy policies
- Design, implementation, and administration of Microsoft Azure environments
- Windows Server 2022 / Windows 11, Windows Group Policy / Active Directory, Remote Desktop Services (RDS), SQL Server 2022 / SCCM Server, RADIUS Server, FSLogix, PowerShell
- Implementation of standard changes according to ITIL guidelines
- VMWare / Splunk
Harshal Likhar
Last position:
SAP EWM Developer at Körber Supply Chain GmbH
- Experience in SAP EWM processes and ABAP development
- Configured PPF for output management in EWM and YM, worked with BOPF in TM and YM, configured Fiori Launchpad with roles, spaces, and pages, and developed UI5 applications
- Developed a Fiori Elements app using the List Report, Object Page, Overview Page, and Analytical List Page frameworks with CDS views, AMDP on BAS, created a RAP app, and a report for data transfer to external Oracle systems
Ehsan Amin
Last position:
Clinical Data Scientist at Freelance
- Conduct data management and statistical analysis for clinical studies on behalf of CROs.
- Guest lecturer at Ivancity University, Paris, specializing in data anonymization techniques and statistical disclosure control.
- Provide scientific and medical writing services for pharmaceutical companies.
- Perform optical mapping data analysis and develop software tools with a focus on algorithm optimization and technical support.
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
2.2 years (Germany: 5.2 years)
Positions per freelancer
13 (Germany: 12)
Top business areas
Information Technology, Product Development, Project Management
Top industries
Information Technology, Manufacturing, Telecommunication
Certification focus areas
Information Technology, Project Management, Product Development
Bachelor's degree or higher
80% (Germany: 89%)
Master's degree or higher
43% (Germany: 59%)
Doctorate
9%
Certifications per freelancer
4 (Germany: 3)
Most common languages
German, English, French
Speak two or more languages
98% (Germany: 97%)
Based on our profile pool as of 30 Aug 2026.
Daily rate distribution
The chart shows how the daily rates of freelancers in this technology in Dusseldorf are distributed, based on recent contracts on our platform. Each bar covers a rate range — its height shows how many freelancers charge within that range.
Average rates of experts in Dusseldorf 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 30 Aug 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
About the technology
Core use
SQL is the language for working with relational data. Companies use it to query records, shape reports, join business tables, and keep applications, dashboards, and internal tools in sync.
What specialists do
- Write and review queries for product, finance, sales, and operations data
- Model tables, keys, indexes, and constraints
- Debug slow queries and broken joins
- Support ETL, ELT, and reporting flows
- Document data logic for teams that share one source of truth
Ecosystem
Strong SQL professionals usually work across PostgreSQL, MySQL, SQL Server, Oracle Database, and SQLite. They also know tools around the query layer, such as dbt, BI tools, warehouse features, and version control for scripts and migrations.
When to bring in help
Companies bring in freelance SQL expertise when reports do not match, queries are slow, data models need cleanup, or a migration is in flight. It is also useful for short projects in Dusseldorf where local teams need extra support on-site, while data work itself can often be done remotely.
What good experts deliver
Good specialists do more than write syntax. They check execution plans, protect data integrity, handle edge cases, and write readable queries that other experts can maintain. They also understand how SQL fits with APIs, application code, and analytics pipelines.
Typical engagement fit
SQL work is often a fit for audits, one-off fixes, warehouse cleanup, and new schema design. It also helps when a team needs help defining metrics, reconciling datasets, or preparing a database for a new application release or reporting layer.
Frequently asked questions
Need clarity? These are the questions we hear most often about SQL.
SQL is used to query, filter, join, and update data in relational databases. Teams rely on it for reporting, dashboards, application back ends, migrations, and data quality checks. It is the standard way to work with tables when business data must stay consistent and easy to search.
SQL is built for structured data with clear relationships, so it is a strong fit for transactions, reporting, and complex joins. NoSQL systems are usually chosen for flexible schemas or very specific access patterns. Many companies use both, but SQL remains the default when data integrity and ad hoc analysis matter.
A strong SQL specialist usually works with PostgreSQL, MySQL, SQL Server, Oracle Database, and sometimes SQLite. The exact stack depends on the application, data warehouse, and cloud setup. Good experts can move between platforms, but they should know the differences in syntax, functions, and tuning.
SQL work becomes more valuable when the specialist also understands data modeling, indexing, query tuning, ETL or ELT, and BI reporting. Familiarity with dbt, Python, shell scripting, and Git is also common. For many projects, the best support comes from someone who can connect database logic with business rules.
A simple query fix may only need a focused SQL expert, while schema redesign, warehouse cleanup, or performance work needs broader experience. The harder the data model and the more systems involved, the more important it becomes to have someone who has solved similar problems before. Good specialists can often scope the risk quickly.
Most SQL work can be done remotely because the core tasks involve queries, schema changes, and analysis in shared environments. On-site time in Dusseldorf can help when teams need close coordination with product, finance, or operations stakeholders. A mixed setup is common when access, reviews, or workshops need direct contact.
Look for clear queries, sound table design, and the ability to explain why a solution is correct. A strong SQL professional checks execution plans, handles nulls and joins carefully, and avoids brittle logic. Ask for examples of performance fixes, migration support, or reporting work that stayed maintainable after handover.
A good SQL freelancer should ask which database is in use, where the data lives, and how the output will be consumed. They should also confirm naming rules, security constraints, and whether the work supports reporting, operations, or an application feature. Clear inputs make the result faster and safer to deliver.
The average hourly rate of freelancers in Dusseldorf, Germany who have used SQL in their recent projects is 94 €, which corresponds to a daily rate of about 750 € based on an 8-hour working day.
Of the freelancers in Dusseldorf, Germany who have used SQL in their recent projects, 80% hold at least a Bachelor's degree, 43% hold at least a Master's degree, and 9% hold a doctorate.
On average, freelancers in Dusseldorf, Germany who have used SQL in their recent projects have 21 years of professional experience, with a single engagement typically lasting around 2.2 years.
The most common languages among freelancers in Dusseldorf, Germany who have used SQL in their recent projects are German (98%), English (96%), and French (15%).
The most common industries among freelancers in Dusseldorf, Germany who have used SQL in their recent projects are Information Technology (80%), Manufacturing (48%), and Telecommunication (46%).
The most common business areas among freelancers in Dusseldorf, Germany who have used SQL in their recent projects are Information Technology (98%), Product Development (67%), and Project Management (59%).
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.
Berlin 
Hamburg 
Munich 
Cologne 
Frankfurt 
Stuttgart 
Leipzig 
Dortmund 
Essen 
Bremen 
Dresden 
Hanover 
Nuremberg Request a free demo
Get in touch with the FRATCH team and we will get back to you within 4 hours.
Would you rather directly get in touch?
We always have the time for a call or email!
Philipp Thomaschewski
FRATCH CEO
