[] (array construction)

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Constructs an array from values of any type.

Syntax

[]
[<value>, ...]

Arguments

ArgumentTypeDescription
<value>Any typeZero or more elements. Types may differ; NULL elements are retained.

Returns

Returns array. With no elements, returns [].

Examples

Collect event labels

Combine fields from a request event into an array of labels:

VALUES ('checkout', 'timeout')
SELECT $0 AS service, $1 AS error
SELECT [service, error] AS labels
+------------------------+
| labels                 |
+------------------------+
| ["checkout","timeout"] |
+------------------------+

Keep structured steps in an event

An array can also contain objects. Keep the name and duration together for each checkout step:

SELECT [
    {'step': 'cart', 'duration_ms': 80},
    {'step': 'payment', 'duration_ms': 245}
] AS steps

The steps value:

[
  {
    "duration_ms": 80,
    "step": "cart"
  },
  {
    "duration_ms": 245,
    "step": "payment"
  }
]