Antigravity Agent
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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.
72 lines
2.9 KiB
Markdown
72 lines
2.9 KiB
Markdown
---
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id: sql-avg
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title: "SQL Avg"
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category: "Database"
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status: "draft"
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verification_status: "conceptual"
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canonical_id: ""
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aliases: ["SQL AVG() Function", "AVG function", "SQL 평균"]
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duplicate_of: ""
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source_trust_level: "B"
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confidence_score: 0.9
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created_at: 2026-07-04
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updated_at: 2026-07-04
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review_reason: ""
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merge_history: []
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tags: ["sql", "database", "w3schools", "avg", "aggregate"]
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raw_sources: ["https://www.w3schools.com/sql/sql_avg.asp"]
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applied_in: []
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github_commit: ""
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---
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# [[SQL Avg]]
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## 🎯 한 줄 통찰 (One-line insight)
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AVG() returns a numeric column's mean, ignoring NULLs, and doubles as a comparison baseline when nested as a subquery in a WHERE clause. [S1]
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## 🧠 핵심 개념 (Core concepts)
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- **AVG() function** — returns the average value of a numeric column; ignores NULL values. [S1]
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- **Syntax** — `SELECT AVG(column_name) FROM table_name WHERE condition;`. [S1]
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- **AVG() with GROUP BY** — returns the average per group. [S1]
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## 🧩 추출된 패턴 (Extracted patterns)
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- **AVG() as a subquery baseline** — `WHERE Price > (SELECT AVG(Price) FROM Products)` uses AVG() inside a subquery to compare each row against the overall average — a reusable pattern for "above/below average" filters. [S1]
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## 📖 세부 내용 (Details)
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- Basic average: `SELECT AVG(Price) FROM Products;`. [S1]
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- With WHERE: `SELECT AVG(Price) FROM Products WHERE CategoryID = 1;`. [S1]
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- With alias: `SELECT AVG(Price) AS [average price] FROM Products;`. [S1]
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- Above-average filter via subquery: `SELECT * FROM Products WHERE Price > (SELECT AVG(Price) FROM Products);`. [S1]
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- With GROUP BY: `SELECT AVG(Price) AS AveragePrice, CategoryID FROM Products GROUP BY CategoryID;`. [S1]
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## ⚖️ 모순 및 업데이트 (Contradictions & updates)
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소스에서 모순되는 정보는 발견되지 않음.
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## 🛠️ 적용 사례 (Applied in summary)
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현재 발견된 실제 적용 사례가 없습니다 — "평균 이상/이하" 필터링은 실무 리포트에서 흔한 패턴이다. [S1]
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## 💻 코드 패턴 (Code patterns)
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Above-average filter using AVG() as subquery (SQL):
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```sql
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SELECT * FROM Products
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WHERE Price > (SELECT AVG(Price) FROM Products);
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```
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## ✅ 검증 상태 및 신뢰도
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- **상태:** draft
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- **검증 단계:** conceptual
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- **출처 신뢰도:** B (W3Schools — widely used educational reference, not a primary standards body)
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- **신뢰 점수:** 0.90
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- **중복 검사 결과:** 신규 생성 (New discovery)
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## 🔗 지식 그래프 (Knowledge Graph)
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- **상위/루트:** [[SQL Tutorial]]
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- **관련 개념:** [[SQL Aggregate Functions]], [[SQL Group By]], [[SQL Where]]
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- **참조 맥락:** 평균값 계산 및 평균 대비 비교 필터링의 기본 함수.
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## 📚 출처 (Sources)
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- [S1] W3Schools — SQL AVG() Function — https://www.w3schools.com/sql/sql_avg.asp
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## 📝 변경 이력 (Change history)
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- 2026-07-04: Initial draft synthesized from the W3Schools "SQL AVG() Function" page (Astra wiki-curation, P-Reinforce v3.1 format).
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