ARRAY_PREPEND

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Syntax

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Scalar

array_prepend(array, element)

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Arguments

• T is the array element type: BOOLEAN, TINYINT, SMALLINT, INTEGER, BIGINT, FLOAT, DOUBLE, DECIMAL(p, s), STRING, BINARY, DATE, TIME, TIMESTAMP, ARRAY, MAP or STRUCT.

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Returns

• Type: ARRAY<T>
• Possible values: The input elements plus the added element.
• NULL behavior: Returns NULL for a NULL array. A NULL element is inserted as a NULL array element.
• Shape: The original length plus one.
• Ordering: Original array order with the added element at the start.

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Properties

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Usage notes

• Pass the array first and the element second. An untyped NULL takes the array’s element type. An array of untyped NULLs takes the supplied element’s type.
• INTEGER and INT mean the same type; STRING means VARCHAR text. NULL can be used with a supported type. Cast NULL explicitly when its type would otherwise be unclear.

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Examples

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Typical behavior

SELECT array_prepend(ARRAY[CAST(1 AS INT), CAST(2 AS INT)], CAST(3 AS INT)) AS "value", array_prepend(ARRAY[CAST(1 AS INT), CAST(2 AS INT)], CAST(NULL AS INT)) AS null_element;

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Prepend a string

SELECT array_prepend(ARRAY('red', 'blue'), 'green') AS colors;

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Limitations

• The element and the array’s elements must have compatible types. Use explicit casts for mixed numeric types.