Array(T)

Array(T) Data Types

ARRAY(T) consists of defined variable-length inner T data type values, which is very similar to a semi-structured ARRAY, except that the inner data type needs to be defined rather than arbitrary. T can be any data type.

note

Databend uses a 1-based numbering convention for arrays. An array of n elements starts with array[1] and ends with array[n].

Example

CREATE TABLE array_int64_table(arr ARRAY(INT64));

DESC array_int64_table;

Result:

┌───────────────────────────────────────────────────┐
│  Field │     Type     │  Null  │ Default │  Extra │
├────────┼──────────────┼────────┼─────────┼────────┤
│ arr    │ ARRAY(INT64) │ YES    │ NULL    │        │
└───────────────────────────────────────────────────┘

-- Inserting array values into the table
INSERT INTO array_int64_table
VALUES
([1, 2, 3, 4]),
([5, 6, 7, 8]);

SELECT arr FROM array_int64_table;

Result:

+-----------+
| arr       |
+-----------+
| [1,2,3,4] |
| [5,6,7,8] |
+-----------+

-- Selecting the zeroth element of the 'arr' array from the table
SELECT arr[0]
FROM array_int64_table;

Result:

┌─────────────────┐
│      arr[0]     │
├─────────────────┤
│            NULL │
│            NULL │
└─────────────────┘