Tuple functions - Clickhouse

:::note The documentation below is generated from the system.functions system table. :::

untuple {#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

sql

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:

text

┌─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:

sql

SELECT untuple(v6) FROM kv;

Result:

text

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

Example of using an EXCEPT expression:

Query:

sql

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

Result:

text

┌─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') │
└─────┴────┴────┴────┴───────────┘

Distance functions {#distance-functions}

All supported functions are described in distance functions documentation.