I will optimize sql queries and build efficient data transformations


About this gig
Do you have slow SQL queries, complex transformations, or database logic that needs improvement?
I will develop, troubleshoot, and optimize SQL queries to improve efficiency, readability, maintainability, and data-processing logic.
I can help with:
- SQL query development and optimization
- Complex joins, CTEs, subqueries, and window functions
- Data cleansing and transformation logic
- Aggregations, calculations, and business rules
- Query troubleshooting and debugging
- Stored procedures and reusable SQL logic
- Performance review and optimization recommendations
- Data validation and reconciliation
- SQL code restructuring and documentation
I focus on more than rewriting SQL. I review the query logic, joins, filters, transformations, and expected results to identify appropriate improvements while preserving business requirements.
I can work with SQL-based environments such as SQL Server, Oracle, PostgreSQL, Teradata, and Databricks/Spark SQL.
Before ordering: Please contact me for complex projects and share your SQL code, database platform, expected output, data volume, and performance issue or business requirement.
Get to know Md K Majumder
Senior Data Engineering and Analytics Expert
- FromCanada
- Member sinceSep 2026
- Avg. response time7 hours
Languages
English
FAQ
FAQ 1 — What types of SQL projects can you help with?
I can help with SQL query development, query optimization, data transformations, complex joins, CTEs, subqueries, window functions, aggregations, business rules, troubleshooting, validation, and SQL code restructuring.
FAQ 2 — Can you optimize slow SQL queries?
Yes. I can review query structure, joins, filters, aggregations, subqueries, CTEs, and other performance-related areas and recommend or implement appropriate improvements. Actual performance gains depend on the database environment, data volume, indexing, and infrastructure.
FAQ 3 — Which SQL platforms can you work with?
can work with SQL-based environments including SQL Server/T-SQL, Oracle SQL/PLSQL, Teradata SQL, Databricks/Spark SQL, PostgreSQL, and other standard SQL environments. Please contact me if you have a specific platform.
FAQ 4 — Can you build complex SQL data transformations?
Yes. I can develop transformation logic involving multiple tables, joins, CTEs, window functions, aggregations, conditional logic, calculations, filtering, cleansing, and business rules.
FAQ 5 — Will you validate the optimized or transformed SQL?
Yes. Where applicable, I can validate record counts, aggregates, key business rules, expected outputs, and transformation results to help ensure that optimization does not change the intended business logic.
FAQ 6 — Can you troubleshoot existing SQL code?
Yes. I can review existing SQL for incorrect results, inefficient logic, problematic joins, duplicate records, filtering issues, transformation errors, and performance concerns, then provide corrected or improved SQL.
FAQ 7 — Should I contact you before placing an order?
For a small and clearly defined SQL task, you can order the appropriate package directly. For complex queries, multiple scripts, stored procedures, large transformations, production workloads, or performance problems, please contact me first so I can review the scope and recommend the appropriate pa

