SQL code completion boosts developer productivity by predicting missing snippets from editing SQL contexts. However, existing solutions yield low acceptance since they cannot abstain when no suggestion is needed and lack SQL-specific training. To address both limitations, we introduce PACE-SQL, a preference-aligned framework that improves SQL completion accuracy and user preference alignment. We build two datasets with completion and abstention samples: WeSQL-1.5M from real-world interaction logs to capture authentic user preferences, and OpenSQL-FIM from public SQL corpora. We adopt continual pretraining and supervised fine-tuning to improve completion quality, and design a reward function in the reinforcement learning to enhance alignment with user preferences. Experiments show PACE-SQL improves Exact Match and Edit Similarity scores by 9.67% and 7.52% over the best baseline on WeSQL-1.5M and raises online user acceptance rate from 5% to 29%.

Retrieval-Augmented Generation (RAG) systems often struggle with imperfect retrieval, as traditional retrievers focus on lexical or semantic similarity rather than logical relevance. To address this, we propose HopRAG, a novel RAG framework that augments retrieval with logical reasoning through graph-structured knowledge exploration. During indexing, HopRAG constructs a passage graph, with text chunks as vertices and logical connections established via LLM-generated pseudo-queries as edges. During retrieval, it employs a retrieve-reason-prune mechanism: starting with lexically or semantically similar passages, the system explores multi-hop neighbors guided by pseudo-queries and LLM reasoning to identify truly relevant ones. Experiments on multiple multi-hop benchmarks demonstrate that HopRAG’s retrieve-reason-prune mechanism can expand the retrieval scope based on logical connections and improve final answer quality.