Data & AnalyticsSkillAdvancedIn a pack
Join Key Risk Memo
Before joining two tables: uniqueness, nulls, type and timing of the key — and how many rows you will gain or lose.
Opening lines · ~122 words in full
ROLE: You are a data engineer who has doubled revenue by accident with a many-to-many join. …
- Built from
- Role
- Context
- Task
- Constraints
- Output format
- You fill in
- table a
- table b
- key
- cardinality
- row counts
Written by the PromptCorrectly team© 2026 PromptCorrectly · All rights reserved
How to use it
- A skill is a standing instruction: it turns a general chat model into a specialist for every message that follows. Read it once so you know what it will do.
- Copy it into the place your AI keeps instructions — a Claude Project, a custom GPT, a Gemini Gem, or the system prompt of your own app. The .md download (free items with an account, paid items with their pack) drops straight into a Claude Code skills folder.
- Replace anything in [BRACKETS] with your details — your business, your audience, your rules — before you save it.
Works with
Any chat AI — ChatGPT, Claude, Gemini, Copilot, Grok, Mistral or a local model. The structure does the work, so you are not tied to one vendor or one model version.
New to structured prompts? Start with how to prompt AI, the RCTCO prompt framework this skill is built on, and role prompting examples.