docs(10_Wiki): Dev 폴더 누락분 반영 — Topic_Programming으로 통합

이전 재구성 작업에서 Dev/ 폴더가 누락되었던 것을 반영. - Dev/Topic_Programming(중첩 폴더, 78개)은 Dev 자체 최상위 폴더들 (Architecture/Conventions/Engineering_Intelligence 등)과 완전 중복이라 제거. - Dev 최상위 엔지니어링 지식 폴더(Architecture/Conventions/Engineering_Intelligence/ Failure_Library/Generalized_Principles/Language/Pattern_Catalog/Platform_Guides/ Subsystems, 77개)는 이미 Topic_Programming/Topic_Programming에 더 최신 버전이 존재해 중복 제거(고유 콘텐츠 1개는 예외 처리하여 이동 보존). - Dev의 W3Schools 언어 튜토리얼 폴더(Topic_C/CPP/CSS/CSharp/HOWTO/HTML/Java/ JavaScript/PHP/Python/SQL/W3CSS, 1201개)는 전부 Topic_Programming 하위로 이동. - 에이전트 운영 상태(.astra/docs)는 그대로 유지, 콘텐츠 폴더만 정리. - Topic_Programming 최종 문서 수: 2784 → 3985.
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+---
+id: sql-in
+title: "SQL In"
+category: "Database"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["SQL IN Operator", "IN operator", "SQL 포함 연산자"]
+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: ["sql", "database", "w3schools", "in", "subquery", "where"]
+raw_sources: ["https://www.w3schools.com/sql/sql_in.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[SQL In]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+IN is a shorthand for multiple OR conditions on the same column, and can take either a literal value list or a subquery result set. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **IN operator** — checks if a column's value matches any value within a provided list, functioning as shorthand for chained OR conditions. [S1]
+- **Syntax** — `SELECT column_name(s) FROM table_name WHERE column_name IN (value1, value2, ...);`. [S1]
+- **NOT IN** — returns records whose value is NOT any of the listed values. [S1]
+- **IN (SELECT ...)** — the value list can be replaced with a subquery, returning rows present in the subquery's result. [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **IN as OR-shorthand** — `WHERE Country IN ('Germany','France','UK')` is equivalent to, and shorter/more readable than, `WHERE Country='Germany' OR Country='France' OR Country='UK'`. [S1]
+- **Subquery membership test** — `WHERE CustomerID IN (SELECT CustomerID FROM Orders)` filters the outer query to rows whose key appears in a related table's query result — a lightweight alternative to a JOIN when only filtering (not selecting extra columns) is needed. [S1]
+
+## 📖 세부 내용 (Details)
+- Literal list form: `SELECT * FROM Customers WHERE Country IN ('Germany', 'France', 'UK');` — equivalent longer form: `WHERE Country = 'Germany' OR Country = 'France' OR Country = 'UK';`. [S1]
+- Negated list form: `WHERE Country NOT IN ('Germany', 'France', 'UK');`. [S1]
+- Subquery form: `WHERE CustomerID IN (SELECT CustomerID FROM Orders);` returns customers who have placed at least one order. [S1]
+- Negated subquery form: `WHERE CustomerID NOT IN (SELECT CustomerID FROM Orders);` returns customers who have never placed an order. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+소스에서 모순되는 정보는 발견되지 않음.
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — 실제 예제에서 "74개 레코드가 반환되었으므로 17명의 고객이 주문이 없다"는 식으로 IN/NOT IN 결과를 상호 검증하는 방식이 소스에 등장한다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+Value-list IN (SQL):
+```sql
+SELECT * FROM Customers
+WHERE Country IN ('Germany', 'France', 'UK');
+```
+Subquery IN (SQL):
+```sql
+SELECT * FROM Customers
+WHERE CustomerID IN (SELECT CustomerID FROM Orders);
+```
+
+## ✅ 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:** [[SQL Tutorial]]
+- **관련 개념:** [[SQL Or]], [[SQL Between]], [[SQL Exists]], [[SQL Where]]
+- **참조 맥락:** 동일 컬럼에 대한 다중 OR 조건이나 서브쿼리 멤버십 테스트가 필요할 때 재사용.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — SQL IN Operator — https://www.w3schools.com/sql/sql_in.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "SQL IN Operator" page (Astra wiki-curation, P-Reinforce v3.1 format).