ClickHouse/docs/en/sql-reference/functions/tuple-functions.md

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66	Tuples

Functions for Working with Tuples

tuple

A function that allows grouping multiple columns. For columns with the types T1, T2, …, it returns a Tuple(T1, T2, …) type tuple containing these columns. There is no cost to execute the function. Tuples are normally used as intermediate values for an argument of IN operators, or for creating a list of formal parameters of lambda functions. Tuples can’t be written to a table.

The function implements the operator (x, y, …).

Syntax

tuple(x, y, …)

tupleElement

A function that allows getting a column from a tuple. ‘N’ is the column index, starting from 1. N must be a constant. ‘N’ must be a constant. ‘N’ must be a strict postive integer no greater than the size of the tuple. There is no cost to execute the function.

The function implements the operator x.N.

Syntax

tupleElement(tuple, n)

untuple

Performs syntactic substitution of tuple elements in the call location.

Syntax

untuple(x)

You can use the EXCEPT expression to skip columns as a result of the query.

Arguments

• x — A tuple function, column, or tuple of elements. Tuple.

Returned value

• None.

Examples

Input table:

┌─key─┬─v1─┬─v2─┬─v3─┬─v4─┬─v5─┬─v6────────┐
│   1 │ 10 │ 20 │ 40 │ 30 │ 15 │ (33,'ab') │
│   2 │ 25 │ 65 │ 70 │ 40 │  6 │ (44,'cd') │
│   3 │ 57 │ 30 │ 20 │ 10 │  5 │ (55,'ef') │
│   4 │ 55 │ 12 │  7 │ 80 │ 90 │ (66,'gh') │
│   5 │ 30 │ 50 │ 70 │ 25 │ 55 │ (77,'kl') │
└─────┴────┴────┴────┴────┴────┴───────────┘

Example of using a Tuple-type column as the untuple function parameter:

Query:

SELECT untuple(v6) FROM kv;

Result:

┌─_ut_1─┬─_ut_2─┐
│    33 │ ab    │
│    44 │ cd    │
│    55 │ ef    │
│    66 │ gh    │
│    77 │ kl    │
└───────┴───────┘

Note: the names are implementation specific and are subject to change. You should not assume specific names of the columns after application of the untuple.

Example of using an EXCEPT expression:

Query:

SELECT untuple((* EXCEPT (v2, v3),)) FROM kv;

Result:

┌─key─┬─v1─┬─v4─┬─v5─┬─v6────────┐
│   1 │ 10 │ 30 │ 15 │ (33,'ab') │
│   2 │ 25 │ 40 │  6 │ (44,'cd') │
│   3 │ 57 │ 10 │  5 │ (55,'ef') │
│   4 │ 55 │ 80 │ 90 │ (66,'gh') │
│   5 │ 30 │ 25 │ 55 │ (77,'kl') │
└─────┴────┴────┴────┴───────────┘

See Also

• Tuple

tupleHammingDistance

Returns the Hamming Distance between two tuples of the same size.

Syntax

tupleHammingDistance(tuple1, tuple2)

Arguments

• tuple1 — First tuple. Tuple.
• tuple2 — Second tuple. Tuple.

Tuples should have the same type of the elements.

Returned value

• The Hamming distance.

Type: UInt8.

Examples

Query:

SELECT tupleHammingDistance((1, 2, 3), (3, 2, 1)) AS HammingDistance;

Result:

┌─HammingDistance─┐
│               2 │
└─────────────────┘

Can be used with MinHash functions for detection of semi-duplicate strings:

SELECT tupleHammingDistance(wordShingleMinHash(string), wordShingleMinHashCaseInsensitive(string)) as HammingDistance FROM (SELECT 'ClickHouse is a column-oriented database management system for online analytical processing of queries.' AS string);

Result:

┌─HammingDistance─┐
│               2 │
└─────────────────┘

tupleToNameValuePairs

Turns a named tuple into an array of (name, value) pairs. For a Tuple(a T, b T, ..., c T) returns Array(Tuple(String, T), ...) in which the Strings represents the named fields of the tuple and T are the values associated with those names. All values in the tuple should be of the same type.

Syntax

tupleToNameValuePairs(tuple)

Arguments

• tuple — Named tuple. Tuple with any types of values.

Returned value

• An array with (name, value) pairs.

Type: Array(Tuple(String, ...)).

Example

Query:

CREATE TABLE tupletest (`col` Tuple(user_ID UInt64, session_ID UInt64) ENGINE = Memory;

INSERT INTO tupletest VALUES (tuple( 100, 2502)), (tuple(1,100));

SELECT tupleToNameValuePairs(col) FROM tupletest;

Result:

┌─tupleToNameValuePairs(col)────────────┐
│ [('user_ID',100),('session_ID',2502)] │
│ [('user_ID',1),('session_ID',100)]    │
└───────────────────────────────────────┘

It is possible to transform colums to rows using this function:

CREATE TABLE tupletest (`col` Tuple(CPU Float64, Memory Float64, Disk Float64)) ENGINE = Memory;

INSERT INTO tupletest VALUES(tuple(3.3, 5.5, 6.6));

SELECT arrayJoin(tupleToNameValuePairs(col))FROM tupletest;

Result:

┌─arrayJoin(tupleToNameValuePairs(col))─┐
│ ('CPU',3.3)                           │
│ ('Memory',5.5)                        │
│ ('Disk',6.6)                          │
└───────────────────────────────────────┘

If you pass a simple tuple to the function, ClickHouse uses the indexes of the values as their names:

SELECT tupleToNameValuePairs(tuple(3, 2, 1));

Result:

┌─tupleToNameValuePairs(tuple(3, 2, 1))─┐
│ [('1',3),('2',2),('3',1)]             │
└───────────────────────────────────────┘

tuplePlus

Calculates the sum of corresponding values of two tuples of the same size.

Syntax

tuplePlus(tuple1, tuple2)

Alias: vectorSum.

Arguments

• tuple1 — First tuple. Tuple.
• tuple2 — Second tuple. Tuple.

Returned value

• Tuple with the sum.

Type: Tuple.

Example

Query:

SELECT tuplePlus((1, 2), (2, 3));

Result:

┌─tuplePlus((1, 2), (2, 3))─┐
│ (3,5)                     │
└───────────────────────────┘

tupleMinus

Calculates the subtraction of corresponding values of two tuples of the same size.

Syntax

tupleMinus(tuple1, tuple2)

Alias: vectorDifference.

Arguments

• tuple1 — First tuple. Tuple.
• tuple2 — Second tuple. Tuple.

Returned value

• Tuple with the result of subtraction.

Type: Tuple.

Example

Query:

SELECT tupleMinus((1, 2), (2, 3));

Result:

┌─tupleMinus((1, 2), (2, 3))─┐
│ (-1,-1)                    │
└────────────────────────────┘

tupleMultiply

Calculates the multiplication of corresponding values of two tuples of the same size.

Syntax

tupleMultiply(tuple1, tuple2)

Arguments

• tuple1 — First tuple. Tuple.
• tuple2 — Second tuple. Tuple.

Returned value

• Tuple with the multiplication.

Type: Tuple.

Example

Query:

SELECT tupleMultiply((1, 2), (2, 3));

Result:

┌─tupleMultiply((1, 2), (2, 3))─┐
│ (2,6)                         │
└───────────────────────────────┘

tupleDivide

Calculates the division of corresponding values of two tuples of the same size. Note that division by zero will return inf.

Syntax

tupleDivide(tuple1, tuple2)

Arguments

• tuple1 — First tuple. Tuple.
• tuple2 — Second tuple. Tuple.

Returned value

• Tuple with the result of division.

Type: Tuple.

Example

Query:

SELECT tupleDivide((1, 2), (2, 3));

Result:

┌─tupleDivide((1, 2), (2, 3))─┐
│ (0.5,0.6666666666666666)    │
└─────────────────────────────┘

tupleNegate

Calculates the negation of the tuple values.

Syntax

tupleNegate(tuple)

Arguments

• tuple — Tuple.

Returned value

• Tuple with the result of negation.

Type: Tuple.

Example

Query:

SELECT tupleNegate((1,  2));

Result:

┌─tupleNegate((1, 2))─┐
│ (-1,-2)             │
└─────────────────────┘

tupleMultiplyByNumber

Returns a tuple with all values multiplied by a number.

Syntax

tupleMultiplyByNumber(tuple, number)

Arguments

• tuple — Tuple.
• number — Multiplier. Int/UInt, Float or Decimal.

Returned value

• Tuple with multiplied values.

Type: Tuple.

Example

Query:

SELECT tupleMultiplyByNumber((1, 2), -2.1);

Result:

┌─tupleMultiplyByNumber((1, 2), -2.1)─┐
│ (-2.1,-4.2)                         │
└─────────────────────────────────────┘

tupleDivideByNumber

Returns a tuple with all values divided by a number. Note that division by zero will return inf.

Syntax

tupleDivideByNumber(tuple, number)

Arguments

• tuple — Tuple.
• number — Divider. Int/UInt, Float or Decimal.

Returned value

• Tuple with divided values.

Type: Tuple.

Example

Query:

SELECT tupleDivideByNumber((1, 2), 0.5);

Result:

┌─tupleDivideByNumber((1, 2), 0.5)─┐
│ (2,4)                            │
└──────────────────────────────────┘

dotProduct

Calculates the scalar product of two tuples of the same size.

Syntax

dotProduct(tuple1, tuple2)

Alias: scalarProduct.

Arguments

• tuple1 — First tuple. Tuple.
• tuple2 — Second tuple. Tuple.

Returned value

• Scalar product.

Type: Int/UInt, Float or Decimal.

Example

Query:

SELECT dotProduct((1, 2), (2, 3));

Result:

┌─dotProduct((1, 2), (2, 3))─┐
│                          8 │
└────────────────────────────┘

L1Norm

Calculates the sum of absolute values of a tuple.

Syntax

L1Norm(tuple)

Alias: normL1.

Arguments

• tuple — Tuple.

Returned value

• L1-norm or taxicab geometry distance.

Type: UInt, Float or Decimal.

Example

Query:

SELECT L1Norm((1, 2));

Result:

┌─L1Norm((1, 2))─┐
│              3 │
└────────────────┘

L2Norm

Calculates the square root of the sum of the squares of the tuple values.

Syntax

L2Norm(tuple)

Alias: normL2.

Arguments

• tuple — Tuple.

Returned value

• L2-norm or Euclidean distance.

Type: Float.

Example

Query:

SELECT L2Norm((1, 2));

Result:

┌───L2Norm((1, 2))─┐
│ 2.23606797749979 │
└──────────────────┘

LinfNorm

Calculates the maximum of absolute values of a tuple.

Syntax

LinfNorm(tuple)

Alias: normLinf.

Arguments

• tuple — Tuple.

Returned value

• Linf-norm or the maximum absolute value.

Type: Float.

Example

Query:

SELECT LinfNorm((1, -2));

Result:

┌─LinfNorm((1, -2))─┐
│                 2 │
└───────────────────┘

LpNorm

Calculates the root of p-th power of the sum of the absolute values of a tuple in the power of p.

Syntax

LpNorm(tuple, p)

Alias: normLp.

Arguments

• tuple — Tuple.
• p — The power. Possible values: real number in [1; inf). UInt or Float.

Returned value

• Lp-norm

Type: Float.

Example

Query:

SELECT LpNorm((1, -2), 2);

Result:

┌─LpNorm((1, -2), 2)─┐
│   2.23606797749979 │
└────────────────────┘

L1Distance

Calculates the distance between two points (the values of the tuples are the coordinates) in L1 space (1-norm (taxicab geometry distance)).

Syntax

L1Distance(tuple1, tuple2)

Alias: distanceL1.

Arguments

• tuple1 — First tuple. Tuple.
• tuple1 — Second tuple. Tuple.

Returned value

• 1-norm distance.

Type: Float.

Example

Query:

SELECT L1Distance((1, 2), (2, 3));

Result:

┌─L1Distance((1, 2), (2, 3))─┐
│                          2 │
└────────────────────────────┘

L2Distance

Calculates the distance between two points (the values of the tuples are the coordinates) in Euclidean space (Euclidean distance).

Syntax

L2Distance(tuple1, tuple2)

Alias: distanceL2.

Arguments

• tuple1 — First tuple. Tuple.
• tuple1 — Second tuple. Tuple.

Returned value

• 2-norm distance.

Type: Float.

Example

Query:

SELECT L2Distance((1, 2), (2, 3));

Result:

┌─L2Distance((1, 2), (2, 3))─┐
│         1.4142135623730951 │
└────────────────────────────┘

LinfDistance

Calculates the distance between two points (the values of the tuples are the coordinates) in L_{inf} space (maximum norm).

Syntax

LinfDistance(tuple1, tuple2)

Alias: distanceLinf.

Arguments

• tuple1 — First tuple. Tuple.
• tuple1 — Second tuple. Tuple.

Returned value

• Infinity-norm distance.

Type: Float.

Example

Query:

SELECT LinfDistance((1, 2), (2, 3));

Result:

┌─LinfDistance((1, 2), (2, 3))─┐
│                            1 │
└──────────────────────────────┘

LpDistance

Calculates the distance between two points (the values of the tuples are the coordinates) in Lp space (p-norm distance).

Syntax

LpDistance(tuple1, tuple2, p)

Alias: distanceLp.

Arguments

• tuple1 — First tuple. Tuple.
• tuple1 — Second tuple. Tuple.
• p — The power. Possible values: real number from [1; inf). UInt or Float.

Returned value

• p-norm distance.

Type: Float.

Example

Query:

SELECT LpDistance((1, 2), (2, 3), 3);

Result:

┌─LpDistance((1, 2), (2, 3), 3)─┐
│            1.2599210498948732 │
└───────────────────────────────┘

L1Normalize

Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in L1 space (taxicab geometry).

Syntax

L1Normalize(tuple)

Alias: normalizeL1.

Arguments

• tuple — Tuple.

Returned value

• Unit vector.

Type: Tuple of Float.

Example

Query:

SELECT L1Normalize((1, 2));

Result:

┌─L1Normalize((1, 2))─────────────────────┐
│ (0.3333333333333333,0.6666666666666666) │
└─────────────────────────────────────────┘

L2Normalize

Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in Euclidean space (using Euclidean distance).

Syntax

L2Normalize(tuple)

Alias: normalizeL1.

Arguments

• tuple — Tuple.

Returned value

• Unit vector.

Type: Tuple of Float.

Example

Query:

SELECT L2Normalize((3, 4));

Result:

┌─L2Normalize((3, 4))─┐
│ (0.6,0.8)           │
└─────────────────────┘

LinfNormalize

Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in L_{inf} space (using maximum norm).

Syntax

LinfNormalize(tuple)

Alias: normalizeLinf .

Arguments

• tuple — Tuple.

Returned value

• Unit vector.

Type: Tuple of Float.

Example

Query:

SELECT LinfNormalize((3, 4));

Result:

┌─LinfNormalize((3, 4))─┐
│ (0.75,1)              │
└───────────────────────┘

LpNormalize

Calculates the unit vector of a given vector (the values of the tuple are the coordinates) in Lp space (using p-norm).

Syntax

LpNormalize(tuple, p)

Alias: normalizeLp .

Arguments

• tuple — Tuple.
• p — The power. Possible values: any number from [1;inf). UInt or Float.

Returned value

• Unit vector.

Type: Tuple of Float.

Example

Query:

SELECT LpNormalize((3, 4),5);

Result:

┌─LpNormalize((3, 4), 5)──────────────────┐
│ (0.7187302630182624,0.9583070173576831) │
└─────────────────────────────────────────┘

cosineDistance

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.

Syntax

cosineDistance(tuple1, tuple2)

Arguments

• tuple1 — First tuple. Tuple.
• tuple2 — Second tuple. Tuple.

Returned value

• Cosine of the angle between two vectors substracted from one.

Type: Float.

Example

Query:

SELECT cosineDistance((1, 2), (2, 3));

Result:

┌─cosineDistance((1, 2), (2, 3))─┐
│           0.007722123286332261 │
└────────────────────────────────┘