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72 lines
1.7 KiB
Markdown
72 lines
1.7 KiB
Markdown
---
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slug: /en/sql-reference/aggregate-functions/reference/cramersv
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sidebar_position: 351
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---
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# cramersV
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[Cramér's V](https://en.wikipedia.org/wiki/Cram%C3%A9r%27s_V) (sometimes referred to as Cramér's phi) is a measure of association between two columns in a table. The result of the `cramersV` function ranges from 0 (corresponding to no association between the variables) to 1 and can reach 1 only when each value is completely determined by the other. It may be viewed as the association between two variables as a percentage of their maximum possible variation.
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**Syntax**
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``` sql
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cramersV(column1, column2)
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```
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**Arguments**
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- `column1` and `column2` are the columns to be compared
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**Returned value**
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- a value between 0 (corresponding to no association between the columns' values) to 1 (complete association).
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**Return type** is always [Float64](../../../sql-reference/data-types/float.md).
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**Example**
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The following two columns being compared below have no association with each other, so the result of `cramersV` is 0:
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``` sql
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SELECT
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cramersV(a, b)
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FROM
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(
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SELECT
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number % 3 AS a,
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number % 5 AS b
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FROM
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numbers(150)
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);
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```
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Result:
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```response
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┌─cramersV(a, b)─┐
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│ 0 │
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└────────────────┘
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```
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The following two columns below have a fairly close association, so the result of `cramersV` is a high value:
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```sql
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SELECT
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cramersV(a, b)
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FROM
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(
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SELECT
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number % 10 AS a,
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number % 5 AS b
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FROM
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numbers(150)
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);
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```
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Result:
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```response
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┌─────cramersV(a, b)─┐
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│ 0.8944271909999159 │
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└────────────────────┘
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``` |