Natural Language Interfaces for Databases: What Do Users Think?

Natural Language Interfaces for Databases (NLIDBs) aim to make database querying accessible by allowing users to ask questions in everyday language rather than using formal SQL queries. Despite significant advancements in translation accuracy, critical usability challenges, such as user frustration, query refinement strategies, and error recovery, remain underexplored. To investigate these usability dimensions, we conducted a mixed-method user study comparing SQL-LLM, a state-of-the-art NL2SQL system, with Snowflake, a traditional SQL analytics platform. Our controlled evaluation involved 20 participants completing realistic database querying tasks across 12 queries each. Results show that SQL-LLM significantly reduced query completion times by 10 to 30 percent (mean: 418 s vs. 629 s, p = 0.036) and improved overall accuracy from 50 to 75 percent (p = 0.002). Additionally, participants using SQL-LLM exhibited fewer query reformulations, recovered from errors 30 to 40 seconds faster, and reported lower frustration levels compared to Snowflake users. Behavioral analysis revealed that SQL-LLM encouraged structured, schema-first querying strategies, enhancing user confidence and efficiency, particularly for complex queries. These findings underscore the practical significance of well-designed, user-friendly NLIDBs in business analytics settings, emphasizing the critical role of usability alongside technical accuracy in real-world deployments.