One innovative use case I've come across is using SQL for recommender systems, where you can leverage the power of SQL to analyze large data sets and make personalized recommendations. This can be applied in e-commerce, content streaming platforms, or even in healthcare.

Another interesting application of SQL is in fraud detection. By combining SQL with machine learning algorithms, you can identify patterns and anomalies in transactional data to proactively detect and prevent fraudulent activities.

I have seen SQL being used in log analysis for system monitoring and debugging. With SQL, you can efficiently analyze logs to gain insights into system performance, identify bottlenecks, and optimize the overall performance of a system.

One interesting use case for SQL is in social network analysis. By representing social relationships and interactions in a relational database, you can use SQL to perform advanced queries to uncover insights about community structures, influence propagation, and user behavior.

SQL can also be used in geospatial analysis, where you can leverage spatial functions and data types to perform complex queries on geographic data. This can be useful in various domains like urban planning, logistics, and environmental monitoring.