Relational Data - Functions - Tuple Functions

From FojiSoft Docs
Revision as of 18:52, 28 August 2024 by Chris.Hansen (talk | contribs) (Import ClickHouse Docs: Wed Aug 28 2024 14:52:37 GMT-0400 (Eastern Daylight Time))
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

tuple

A function that allows grouping multiple columns. For columns C1, C2, … with the types T1, T2, …, it returns a named Tuple(C1 T1, C2 T2, …) type tuple containing these columns if their names are unique and can be treated as unquoted identifiers, otherwise a Tuple(T1, T2, …) is returned. 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.

If the second argument is a number index, it is the column index, starting from 1. If the second argument is a string name, it represents the name of the element. Besides, we can provide the third optional argument, such that when index out of bounds or no element exist for the name, the default value returned instead of throwing an exception. The second and third arguments, if provided, must be constants. There is no cost to execute the function.

The function implements operators x.index and x.name.

Syntax 

tupleElement(tuple, index, [, default_value])
tupleElement(tuple, name, [, default_value])

untuple

Performs syntactic substitution of tuple elements in the call location.

The names of the result columns are implementation-specific and subject to change. Do not assume specific column names after untuple.

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    │
└───────┴───────┘

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

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.

The result type is calculated the same way it is for Arithmetic functions, based on the number of elements in the input tuples. 


SELECT
    toTypeName(tupleHammingDistance(tuple(0), tuple(0))) AS t1,
    toTypeName(tupleHammingDistance((0, 0), (0, 0))) AS t2,
    toTypeName(tupleHammingDistance((0, 0, 0), (0, 0, 0))) AS t3,
    toTypeName(tupleHammingDistance((0, 0, 0, 0), (0, 0, 0, 0))) AS t4,
    toTypeName(tupleHammingDistance((0, 0, 0, 0, 0), (0, 0, 0, 0, 0))) AS t5
┌─t1────┬─t2─────┬─t3─────┬─t4─────┬─t5─────┐
│ UInt8 │ UInt16 │ UInt32 │ UInt64 │ UInt64 │
└───────┴────────┴────────┴────────┴────────┘

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

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 columns 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)]             │
└───────────────────────────────────────┘

tupleNames

Converts a tuple into an array of column names. For a tuple in the form Tuple(a T, b T, ...), it returns an array of strings representing the named columns of the tuple. If the tuple elements do not have explicit names, their indices will be used as the column names instead.

Syntax 

tupleNames(tuple)

Arguments

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

Returned value

  • An array with strings.

Type: Array(Tuple(String, …)).

Example

Query: 

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

INSERT INTO tupletest VALUES (tuple(1, 2));

SELECT tupleNames(col) FROM tupletest;

Result: 

┌─tupleNames(col)──────────┐
│ ['user_ID','session_ID'] │
└──────────────────────────┘

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

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

Result: 

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

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. 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. 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. 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. 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

Returned value

  • Tuple with the result of negation. 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

Returned value

  • Tuple with multiplied values. 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

Returned value

  • Tuple with divided values. Tuple.

Example

Query: 

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

Result: 

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

tupleConcat

Combines tuples passed as arguments. 

tupleConcat(tuples)

Arguments

  • tuples – Arbitrary number of arguments of Tuple type.

Example 

SELECT tupleConcat((1, 2), (3, 4), (true, false)) AS res
┌─res──────────────────┐
│ (1,2,3,4,true,false) │
└──────────────────────┘

tupleIntDiv

Does integer division of a tuple of numerators and a tuple of denominators, and returns a tuple of the quotients.

Syntax 

tupleIntDiv(tuple_num, tuple_div)

Parameters

  • tuple_num: Tuple of numerator values. Tuple of numeric type.
  • tuple_div: Tuple of divisor values. Tuple of numeric type.

Returned value

  • Tuple of the quotients of tuple_num and tuple_div. Tuple of integer values.

Implementation details

  • If either tuple_num or tuple_div contain non-integer values then the result is calculated by rounding to the nearest integer for each non-integer numerator or divisor.
  • An error will be thrown for division by 0.

Examples

Query: 

SELECT tupleIntDiv((15, 10, 5), (5, 5, 5));

Result: 

┌─tupleIntDiv((15, 10, 5), (5, 5, 5))─┐
│ (3,2,1)                             │
└─────────────────────────────────────┘

Query: 

SELECT tupleIntDiv((15, 10, 5), (5.5, 5.5, 5.5));

Result: 

┌─tupleIntDiv((15, 10, 5), (5.5, 5.5, 5.5))─┐
│ (2,1,0)                                   │
└───────────────────────────────────────────┘

tupleIntDivOrZero

Like tupleIntDiv it does integer division of a tuple of numerators and a tuple of denominators, and returns a tuple of the quotients. It does not throw an error for 0 divisors, but rather returns the quotient as 0.

Syntax 

tupleIntDivOrZero(tuple_num, tuple_div)
  • tuple_num: Tuple of numerator values. Tuple of numeric type.
  • tuple_div: Tuple of divisor values. Tuple of numeric type.

Returned value

  • Tuple of the quotients of tuple_num and tuple_div. Tuple of integer values.
  • Returns 0 for quotients where the divisor is 0.

Implementation details

  • If either tuple_num or tuple_div contain non-integer values then the result is calculated by rounding to the nearest integer for each non-integer numerator or divisor as in tupleIntDiv.

Examples

Query: 

SELECT tupleIntDivOrZero((5, 10, 15), (0, 0, 0));

Result: 

┌─tupleIntDivOrZero((5, 10, 15), (0, 0, 0))─┐
│ (0,0,0)                                   │
└───────────────────────────────────────────┘

tupleIntDivByNumber

Does integer division of a tuple of numerators by a given denominator, and returns a tuple of the quotients.

Syntax 

tupleIntDivByNumber(tuple_num, div)

Parameters

  • tuple_num: Tuple of numerator values. Tuple of numeric type.
  • div: The divisor value. Numeric type.

Returned value

  • Tuple of the quotients of tuple_num and div. Tuple of integer values.

Implementation details

  • If either tuple_num or div contain non-integer values then the result is calculated by rounding to the nearest integer for each non-integer numerator or divisor.
  • An error will be thrown for division by 0.

Examples

Query: 

SELECT tupleIntDivByNumber((15, 10, 5), 5);

Result: 

┌─tupleIntDivByNumber((15, 10, 5), 5)─┐
│ (3,2,1)                             │
└─────────────────────────────────────┘

Query: 

SELECT tupleIntDivByNumber((15.2, 10.7, 5.5), 5.8);

Result: 

┌─tupleIntDivByNumber((15.2, 10.7, 5.5), 5.8)─┐
│ (2,1,0)                                     │
└─────────────────────────────────────────────┘

tupleIntDivOrZeroByNumber

Like tupleIntDivByNumber it does integer division of a tuple of numerators by a given denominator, and returns a tuple of the quotients. It does not throw an error for 0 divisors, but rather returns the quotient as 0.

Syntax 

tupleIntDivOrZeroByNumber(tuple_num, div)

Parameters

  • tuple_num: Tuple of numerator values. Tuple of numeric type.
  • div: The divisor value. Numeric type.

Returned value

  • Tuple of the quotients of tuple_num and div. Tuple of integer values.
  • Returns 0 for quotients where the divisor is 0.

Implementation details

  • If either tuple_num or div contain non-integer values then the result is calculated by rounding to the nearest integer for each non-integer numerator or divisor as in tupleIntDivByNumber.

Examples

Query: 

SELECT tupleIntDivOrZeroByNumber((15, 10, 5), 5);

Result: 

┌─tupleIntDivOrZeroByNumber((15, 10, 5), 5)─┐
│ (3,2,1)                                   │
└───────────────────────────────────────────┘

Query: 

SELECT tupleIntDivOrZeroByNumber((15, 10, 5), 0)

Result: 

┌─tupleIntDivOrZeroByNumber((15, 10, 5), 0)─┐
│ (0,0,0)                                   │
└───────────────────────────────────────────┘

tupleModulo

Returns a tuple of the moduli (remainders) of division operations of two tuples.

Syntax 

tupleModulo(tuple_num, tuple_mod)

Parameters

  • tuple_num: Tuple of numerator values. Tuple of numeric type.
  • tuple_div: Tuple of modulus values. Tuple of numeric type.

Returned value

  • Tuple of the remainders of division of tuple_num and tuple_div. Tuple of non-zero integer values.
  • An error is thrown for division by zero.

Examples

Query: 

SELECT tupleModulo((15, 10, 5), (5, 3, 2));

Result: 

┌─tupleModulo((15, 10, 5), (5, 3, 2))─┐
│ (0,1,1)                             │
└─────────────────────────────────────┘

tupleModuloByNumber

Returns a tuple of the moduli (remainders) of division operations of a tuple and a given divisor.

Syntax 

tupleModuloByNumber(tuple_num, div)

Parameters

  • tuple_num: Tuple of numerator values. Tuple of numeric type.
  • div: The divisor value. Numeric type.

Returned value

  • Tuple of the remainders of division of tuple_num and div. Tuple of non-zero integer values.
  • An error is thrown for division by zero.

Examples

Query: 

SELECT tupleModuloByNumber((15, 10, 5), 2);

Result: 

┌─tupleModuloByNumber((15, 10, 5), 2)─┐
│ (1,0,1)                             │
└─────────────────────────────────────┘

flattenTuple

Returns a flattened output tuple from a nested named input tuple. Elements of the output tuple are the paths from the original input tuple. For instance: Tuple(a Int, Tuple(b Int, c Int)) -> Tuple(a Int, b Int, c Int). flattenTuple can be used to select all paths from type Object as separate columns.

Syntax 

flattenTuple(input)

Parameters

  • input: Nested named tuple to flatten. Tuple.

Returned value

  • output tuple whose elements are paths from the original input. Tuple.

Example

Query: 

CREATE TABLE t_flatten_tuple(t Tuple(t1 Nested(a UInt32, s String), b UInt32, t2 Tuple(k String, v UInt32))) ENGINE = Memory;
INSERT INTO t_flatten_tuple VALUES (([(1, 'a'), (2, 'b')], 3, ('c', 4)));
SELECT flattenTuple(t) FROM t_flatten_tuple;

Result: 

┌─flattenTuple(t)───────────┐
│ ([1,2],['a','b'],3,'c',4) │
└───────────────────────────┘

Distance functions

All supported functions are described in distance functions documentation.

Retrieved from "https://docs.foji.io/index.php?title=Relational_Data_-_Functions_-_Tuple_Functions&oldid=2306"