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* prefer relative links from root * wip * split aggregate function reference * split system tables
45 lines
557 B
Markdown
45 lines
557 B
Markdown
---
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toc_priority: 128
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---
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# groupBitmap {#groupbitmap}
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Bitmap or Aggregate calculations from a unsigned integer column, return cardinality of type UInt64, if add suffix -State, then return [bitmap object](../../../sql-reference/functions/bitmap-functions.md).
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``` sql
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groupBitmap(expr)
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```
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**Parameters**
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`expr` – An expression that results in `UInt*` type.
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**Return value**
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Value of the `UInt64` type.
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**Example**
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Test data:
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``` text
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UserID
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1
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1
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2
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3
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```
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Query:
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``` sql
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SELECT groupBitmap(UserID) as num FROM t
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```
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Result:
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``` text
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num
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3
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```
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