docs(10_Wiki): Topic_Business/General/Graphic/Programming을 Topics/ 하위로 이동

최상위 10_Wiki/Topic_*였던 4개 카테고리 폴더를 10_Wiki/Topics/Topic_* 로 재배치. 콘텐츠 변경 없음(순수 폴더 이동) — Topics/ 하위 나머지 폴더는 이미 지난 커밋에서 전부 정리된 상태(잔존 항목은 에이전트 운영 상태 및 사용자가 보존을 요청한 업데이트0615/무제 3.canvas 뿐).
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+---
+id: sql-dates
+title: "SQL Dates"
+category: "Database"
+status: "draft"
+verification_status: "conceptual"
+canonical_id: ""
+aliases: ["SQL Working With Dates", "SQL 날짜"]
+duplicate_of: ""
+source_trust_level: "B"
+confidence_score: 0.88
+created_at: 2026-07-04
+updated_at: 2026-07-04
+review_reason: ""
+merge_history: []
+tags: ["sql", "database", "w3schools", "dates"]
+raw_sources: ["https://www.w3schools.com/sql/sql_dates.asp"]
+applied_in: []
+github_commit: ""
+---
+
+# [[SQL Dates]]
+
+## 🎯 한 줄 통찰 (One-line insight)
+Matching a date literal against a datetime column silently returns nothing if the stored value carries a time component the literal doesn't — the hardest part of SQL dates is format alignment, not date logic itself. [S1]
+
+## 🧠 핵심 개념 (Core concepts)
+- **The core difficulty** — being sure the date format you insert/select matches the database column's format. [S1]
+- **MySQL date types** — `DATE` (YYYY-MM-DD), `DATETIME`/`TIMESTAMP` (YYYY-MM-DD HH:MI:SS), `TIME` (HH:MI:SS), `YEAR` (YYYY or YY). [S1]
+- **SQL Server date types** — `DATE`, `DATETIME`, `SMALLDATETIME`, `TIME`, `TIMESTAMP` (a unique number, not a date). [S1]
+
+## 🧩 추출된 패턴 (Extracted patterns)
+- **Time-component footgun** — a WHERE clause like `OrderDate='2025-11-11'` matches rows when the column is pure `DATE`, but silently returns zero rows once the column stores a time component too (e.g. `2025-11-11 13:23:44`), because exact string/value equality no longer holds. [S1]
+- **Keep dates time-free unless necessary** — the source explicitly recommends avoiding time-components in date columns to keep queries simple, unless the time is actually needed. [S1]
+
+## 📖 세부 내용 (Details)
+- Simple date match (works, no time component): `SELECT * FROM Orders WHERE OrderDate='2025-11-11'`. [S1]
+- Same query against a column that also stores time (returns NO rows, since exact match requires the time portion too): same query, different schema. [S1]
+
+## ⚖️ 모순 및 업데이트 (Contradictions & updates)
+소스에서 모순되는 정보는 발견되지 않음. 다만 "동일해 보이는 쿼리가 스키마에 따라 결과가 완전히 달라진다"는 점이 핵심 경고로 제시됨. [S1]
+
+## 🛠️ 적용 사례 (Applied in summary)
+현재 발견된 실제 적용 사례가 없습니다 — "쿼리가 아무 결과도 안 준다"는 흔한 버그의 원인이 날짜/시간 포맷 불일치인 경우가 많다. [S1]
+
+## 💻 코드 패턴 (Code patterns)
+Exact date match, no time component (SQL):
+```sql
+SELECT * FROM Orders WHERE OrderDate='2025-11-11';
+```
+
+## ✅ 검증 상태 및 신뢰도
+- **상태:** draft
+- **검증 단계:** conceptual
+- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
+- **신뢰 점수:** 0.88
+- **중복 검사 결과:** 신규 생성 (New discovery)
+
+## 🔗 지식 그래프 (Knowledge Graph)
+- **상위/루트:** [[SQL Tutorial]]
+- **관련 개념:** [[SQL Between]], [[SQL Data Types]], [[SQL Where]]
+- **참조 맥락:** 날짜/시간 컬럼을 다루는 모든 쿼리에서 포맷 불일치 버그를 예방하기 위해 참조.
+
+## 📚 출처 (Sources)
+- [S1] W3Schools — SQL Working With Dates — https://www.w3schools.com/sql/sql_dates.asp
+
+## 📝 변경 이력 (Change history)
+- 2026-07-04: Initial draft synthesized from the W3Schools "SQL Working With Dates" page (Astra wiki-curation, P-Reinforce v3.1 format).