ARRAY_DISTINCT

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Syntax

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Scalar

array_distinct(array)

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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 or STRUCT.

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Returns

• Type: ARRAY<T>
• Possible values: The distinct input values.
• NULL behavior: Returns NULL for a NULL array. At most one NULL element remains.
• Shape: Zero through the original number of elements.
• Ordering: First-occurrence encounter order.

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Properties

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Usage notes

• When removing duplicates, all NaN values are treated as equal, as are positive and negative zero.
• 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_distinct(ARRAY[1, 2, 1, NULL, NULL]) AS "value";

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Remove repeated strings

SELECT array_distinct(ARRAY('red', 'blue', 'red')) AS colors;

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Limitations

• Elements must be comparable. MAP elements are not supported, including maps nested inside other elements.
• MAP elements, including MAP values nested inside compared elements, are outside the supported element types.