docs(10_Wiki): 위키 구조 정리 — 언어 튜토리얼 카테고리 폴더 제거 + 신규 자산 동기화

Topic_CSS/Topic_HTML/Topic_JavaScript/Topic_Prompt/Topic_Comfyui 등 기존 카테고리 폴더를 정리하고, Topic_Graphic/Dev 등 신규 산출물과 Topics 내부 세션/메모리 기록을 동기화.
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+---
+id: python-mysql-join
+title: "Python MySQL Join"
+category: "Programming_Language"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["파이썬 MySQL 조인"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.9
+created_at: 2026-07-04
+updated_at: 2026-07-04
+review_reason: ""
+merge_history: []
+tags: ["python", "mysql", "w3schools", "join", "innerjoin", "leftjoin", "rightjoin"]
+raw_sources: ["https://www.w3schools.com/python/python_mysql_join.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[Python MySQL Join]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+INNER JOIN silently drops users with no favorite product (Hannah, Michael) — the same rows only reappear if you switch to LEFT JOIN, making the choice of join type directly visible in which rows survive. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **JOIN via raw SQL** — combining `users` and `products` tables on `users.fav = products.id`, executed through the same cursor pattern. [S1]
+- **INNER JOIN (default via JOIN)** — only matching rows in both tables; users with no favorite product are excluded. [S1]
+- **LEFT JOIN** — keeps ALL users, even those without a matching product (fav is NULL). [S1]
+- **RIGHT JOIN** — keeps ALL products, even those no user has favorited. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Missing rows are the tell** — the source explicitly points out that Hannah and Michael (no favorite product) vanish under INNER/RIGHT JOIN but reappear under LEFT JOIN — a concrete way to verify which join type is actually in effect. [S1]
+
+## 📖 세부 내용 (Details)
+- Sample data: `users` table has `fav` referencing `products.id`; some users (Hannah, Michael) have no `fav` value. [S1]
+- INNER JOIN: `sql = "SELECT users.name AS user, products.name AS favorite FROM users INNER JOIN products ON users.fav = products.id"` — excludes users with no favorite. [S1]
+- LEFT JOIN: same query with `LEFT JOIN` — includes ALL users, even without a favorite. [S1]
+- RIGHT JOIN: same query with `RIGHT JOIN` — includes ALL products, even unfavorited ones; still excludes favorite-less users. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+소스에서 모순되는 정보는 발견되지 않음.
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — SQL Inner/Left/Right Join 챕터에서 이미 배운 동작 차이를 실제 mysql.connector 쿼리로 재확인하는 문서다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+LEFT JOIN to include unmatched rows (Python):
+```python
+sql = "SELECT \
+  users.name AS user, \
+  products.name AS favorite \
+  FROM users \
+  LEFT JOIN products ON users.fav = products.id"
+mycursor.execute(sql)
+myresult = mycursor.fetchall()
+```
+
+## ✅ 검증 상태 및 신뢰도
+- **상태:** draft
+- **검증 단계:** conceptual
+- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
+- **신뢰 점수:** 0.90
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[Python Tutorial]]
+- **관련 개념:** [[SQL Inner Join]], [[SQL Left Join]], [[SQL Right Join]], [[Python MySQL Select]]
+- **참조 맥락:** SQL JOIN 동작 차이를 mysql.connector로 실증 — 사라지는/나타나는 행으로 join 유형을 검증할 수 있다.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — Python MySQL Join — https://www.w3schools.com/python/python_mysql_join.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "Python MySQL Join" page (Astra wiki-curation, P-Reinforce v3.1 format).