32 lines
921 B
Markdown
32 lines
921 B
Markdown
---
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title: "SQL View"
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type: concept
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tags: [数据库, SQL, 数据预处理]
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---
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## Definition
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预处理的数据库视图（View），通过 SQL 查询定义，用于解析 JSON 字段、计算派生指标、聚合数据，使 BI 工具能直接使用数值字段。
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## Common Use Cases
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- 解析 JSON 字段：如 `JSON_EXTRACT(prodct_rating, '$.rating') AS rating`
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- 计算派生指标：如 `(final_price * sold) AS total_gmv`
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- 数据聚合：如按类目汇总销量、销售额
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## Example
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```sql
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CREATE OR REPLACE VIEW view_products_cleaned AS
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SELECT
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id,
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title,
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category,
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final_price,
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sold,
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JSON_EXTRACT(prodct_rating, '$.rating') AS rating,
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JSON_EXTRACT(prodct_rating, '$.count') AS rating_count,
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(final_price * sold) AS total_gmv
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FROM products;
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```
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## Related Concepts
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- [[Apache-Superset]]：使用 SQL View 作为数据集
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- [[JSON-字段解析]]：从 JSON 数据中提取值 |