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---
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toc_priority: 143
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---
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# maxMap {#agg_functions-maxmap}
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**语法**
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2021-02-09 12:47:52 +00:00
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```sql
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maxMap(key, value)
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或
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maxMap(Tuple(key, value))
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```
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根据 `key` 数组中指定的键对 `value` 数组计算最大值。
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传递 `key` 和 `value` 数组的元组与传递 `key` 和 `value` 的两个数组是同义的。
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要总计的每一行的 `key` 和 `value` (数组)元素的数量必须相同。
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返回两个数组组成的元组: 排好序的`key` 和对应 `key` 的 `value` 计算值(最大值)。
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示例:
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``` sql
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SELECT maxMap(a, b)
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FROM values('a Array(Int32), b Array(Int64)', ([1, 2], [2, 2]), ([2, 3], [1, 1]))
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```
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``` text
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┌─maxMap(a, b)──────┐
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│ ([1,2,3],[2,2,1]) │
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└───────────────────┘
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```
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