19 lines
442 B
Markdown
19 lines
442 B
Markdown
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---
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aliases:
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tags:
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- зрелость/🌱
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date:
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- - 2024-02-05
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zero-link:
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- "[[00 Базы Данных]]"
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parents:
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linked:
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---
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B MySQL используется метод nested loops, но с оптимизациями.
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```sql
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SELECT * FROM posts WHERE author = "Peter"
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JOIN comments ON posts. id = comments.post_id
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```
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Индекс по `posts.id` бесполезен. Индекс по `comments.post_id` обязателен.
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