A Complex SQL Query Writing Developer designs, develops, and implements complex SQL queries to manage and manipulate databases effectively. They analyze business requirements and data structures to create optimized, intricate queries. Their tasks include retrieving complex data, developing procedures for data extraction, transformation, and loading (ETL), and ensuring data integrity and security. They also perform database optimization, troubleshoot performance issues, and provide solutions. Additionally, they may design and implement database schemas and create documentation for database designs and architectures. Their role requires extensive knowledge of SQL programming, database systems, and data modeling principles.