RAG query expansion guide compares HyDE with multi-query rewriting

On 2026-11-05 18:42, Juejin published an article titled “RAG Query Expansion in Practice: HyDE versus Multi-query Rewriting — How to Choose and How to Combine”. In an earlier hands-on post, the author had already tackled coreference and ellipsis in multi-turn conversations. The approach there was to restore non-self-contained utterances into standalone queries before feeding them to retrieval. But the new piece argues that a standalone query is still not automatically a good retrieval input, because users and documents rarely describe the same thing in the same words. The article puts it concretely: a user says "the device keeps freezing", while the document says "device response timed out"; a user says printing has dark streaks, and the documentation uses yet another phrasing. Against this mismatch, the post turns to query expansion. It compares HyDE and multi-query rewriting, laying out the scenarios in which each approach fits and discussing how to combine the two in a single pipeline. The materials do not include further details, specific results, or the article's concrete recommendations.