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509 lines
11 KiB
Markdown
509 lines
11 KiB
Markdown
---
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slug: /en/sql-reference/functions/distance-functions
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sidebar_position: 55
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sidebar_label: Distance
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---
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# Distance Functions
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## L1Norm
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Calculates the sum of absolute values of a vector.
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**Syntax**
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```sql
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L1Norm(vector)
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```
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Alias: `normL1`.
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**Arguments**
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- `vector` — [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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**Returned value**
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- L1-norm or [taxicab geometry](https://en.wikipedia.org/wiki/Taxicab_geometry) distance.
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Type: [UInt](../../sql-reference/data-types/int-uint.md), [Float](../../sql-reference/data-types/float.md) or [Decimal](../../sql-reference/data-types/decimal.md).
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**Examples**
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Query:
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```sql
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SELECT L1Norm((1, 2));
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```
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Result:
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```text
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┌─L1Norm((1, 2))─┐
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│ 3 │
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└────────────────┘
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```
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## L2Norm
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Calculates the square root of the sum of the squares of the vector values.
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**Syntax**
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```sql
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L2Norm(vector)
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```
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Alias: `normL2`.
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**Arguments**
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- `vector` — [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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**Returned value**
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- L2-norm or [Euclidean distance](https://en.wikipedia.org/wiki/Euclidean_distance).
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Type: [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT L2Norm((1, 2));
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```
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Result:
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```text
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┌───L2Norm((1, 2))─┐
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│ 2.23606797749979 │
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└──────────────────┘
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```
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## LinfNorm
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Calculates the maximum of absolute values of a vector.
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**Syntax**
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```sql
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LinfNorm(vector)
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```
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Alias: `normLinf`.
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**Arguments**
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- `vector` — [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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**Returned value**
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- Linf-norm or the maximum absolute value.
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Type: [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT LinfNorm((1, -2));
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```
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Result:
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```text
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┌─LinfNorm((1, -2))─┐
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│ 2 │
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└───────────────────┘
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```
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## LpNorm
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Calculates the root of `p`-th power of the sum of the absolute values of a vector in the power of `p`.
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**Syntax**
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```sql
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LpNorm(vector, p)
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```
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Alias: `normLp`.
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**Arguments**
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- `vector` — [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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- `p` — The power. Possible values: real number in `[1; inf)`. [UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
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**Returned value**
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- [Lp-norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#p-norm)
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Type: [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT LpNorm((1, -2), 2);
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```
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Result:
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```text
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┌─LpNorm((1, -2), 2)─┐
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│ 2.23606797749979 │
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└────────────────────┘
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```
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## L1Distance
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Calculates the distance between two points (the values of the vectors are the coordinates) in `L1` space (1-norm ([taxicab geometry](https://en.wikipedia.org/wiki/Taxicab_geometry) distance)).
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**Syntax**
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```sql
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L1Distance(vector1, vector2)
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```
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Alias: `distanceL1`.
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**Arguments**
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- `vector1` — First vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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- `vector2` — Second vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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**Returned value**
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- 1-norm distance.
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Type: [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT L1Distance((1, 2), (2, 3));
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```
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Result:
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```text
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┌─L1Distance((1, 2), (2, 3))─┐
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│ 2 │
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└────────────────────────────┘
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```
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## L2Distance
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Calculates the distance between two points (the values of the vectors are the coordinates) in Euclidean space ([Euclidean distance](https://en.wikipedia.org/wiki/Euclidean_distance)).
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**Syntax**
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```sql
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L2Distance(vector1, vector2)
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```
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Alias: `distanceL2`.
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**Arguments**
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- `vector1` — First vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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- `vector2` — Second vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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**Returned value**
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- 2-norm distance.
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Type: [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT L2Distance((1, 2), (2, 3));
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```
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Result:
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```text
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┌─L2Distance((1, 2), (2, 3))─┐
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│ 1.4142135623730951 │
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└────────────────────────────┘
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```
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## LinfDistance
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Calculates the distance between two points (the values of the vectors are the coordinates) in `L_{inf}` space ([maximum norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#Maximum_norm_(special_case_of:_infinity_norm,_uniform_norm,_or_supremum_norm))).
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**Syntax**
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```sql
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LinfDistance(vector1, vector2)
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```
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Alias: `distanceLinf`.
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**Arguments**
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- `vector1` — First vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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- `vector1` — Second vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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**Returned value**
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- Infinity-norm distance.
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Type: [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT LinfDistance((1, 2), (2, 3));
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```
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Result:
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```text
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┌─LinfDistance((1, 2), (2, 3))─┐
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│ 1 │
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└──────────────────────────────┘
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```
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## LpDistance
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Calculates the distance between two points (the values of the vectors are the coordinates) in `Lp` space ([p-norm distance](https://en.wikipedia.org/wiki/Norm_(mathematics)#p-norm)).
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**Syntax**
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```sql
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LpDistance(vector1, vector2, p)
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```
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Alias: `distanceLp`.
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**Arguments**
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- `vector1` — First vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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- `vector2` — Second vector. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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- `p` — The power. Possible values: real number from `[1; inf)`. [UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
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**Returned value**
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- p-norm distance.
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Type: [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT LpDistance((1, 2), (2, 3), 3);
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```
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Result:
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```text
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┌─LpDistance((1, 2), (2, 3), 3)─┐
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│ 1.2599210498948732 │
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└───────────────────────────────┘
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```
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## L1Normalize
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Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in `L1` space ([taxicab geometry](https://en.wikipedia.org/wiki/Taxicab_geometry)).
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**Syntax**
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```sql
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L1Normalize(tuple)
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```
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Alias: `normalizeL1`.
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**Arguments**
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- `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
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**Returned value**
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- Unit vector.
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Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT L1Normalize((1, 2));
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```
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Result:
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```text
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┌─L1Normalize((1, 2))─────────────────────┐
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│ (0.3333333333333333,0.6666666666666666) │
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└─────────────────────────────────────────┘
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```
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## L2Normalize
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Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in Euclidean space (using [Euclidean distance](https://en.wikipedia.org/wiki/Euclidean_distance)).
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**Syntax**
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```sql
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L2Normalize(tuple)
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```
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Alias: `normalizeL1`.
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**Arguments**
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- `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
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**Returned value**
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- Unit vector.
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Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT L2Normalize((3, 4));
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```
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Result:
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```text
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┌─L2Normalize((3, 4))─┐
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│ (0.6,0.8) │
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└─────────────────────┘
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```
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## LinfNormalize
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Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in `L_{inf}` space (using [maximum norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#Maximum_norm_(special_case_of:_infinity_norm,_uniform_norm,_or_supremum_norm))).
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**Syntax**
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```sql
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LinfNormalize(tuple)
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```
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Alias: `normalizeLinf `.
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**Arguments**
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- `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
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**Returned value**
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- Unit vector.
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Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT LinfNormalize((3, 4));
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```
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Result:
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```text
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┌─LinfNormalize((3, 4))─┐
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│ (0.75,1) │
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└───────────────────────┘
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```
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## LpNormalize
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Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in `Lp` space (using [p-norm](https://en.wikipedia.org/wiki/Norm_(mathematics)#p-norm)).
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**Syntax**
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```sql
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LpNormalize(tuple, p)
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```
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Alias: `normalizeLp `.
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**Arguments**
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- `tuple` — [Tuple](../../sql-reference/data-types/tuple.md).
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- `p` — The power. Possible values: any number from [1;inf). [UInt](../../sql-reference/data-types/int-uint.md) or [Float](../../sql-reference/data-types/float.md).
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**Returned value**
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- Unit vector.
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Type: [Tuple](../../sql-reference/data-types/tuple.md) of [Float](../../sql-reference/data-types/float.md).
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**Example**
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Query:
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```sql
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SELECT LpNormalize((3, 4),5);
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```
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Result:
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```text
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┌─LpNormalize((3, 4), 5)──────────────────┐
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│ (0.7187302630182624,0.9583070173576831) │
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└─────────────────────────────────────────┘
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```
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## cosineDistance
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Calculates the cosine distance between two vectors (the values of the tuples are the coordinates). The less the returned value is, the more similar are the vectors.
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**Syntax**
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```sql
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cosineDistance(vector1, vector2)
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```
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**Arguments**
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- `vector1` — First tuple. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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- `vector2` — Second tuple. [Tuple](../../sql-reference/data-types/tuple.md) or [Array](../../sql-reference/data-types/array.md).
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**Returned value**
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- Cosine of the angle between two vectors subtracted from one.
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Type: [Float](../../sql-reference/data-types/float.md).
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**Examples**
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Query:
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```sql
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SELECT cosineDistance((1, 2), (2, 3));
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```
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Result:
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```text
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┌─cosineDistance((1, 2), (2, 3))─┐
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│ 0.007722123286332261 │
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└────────────────────────────────┘
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```
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