array_agg aggregate function

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime 10.4 LTS and above

Returns an array consisting of all values in expr within the group. This function is a synonym for collect_list aggregate function.

Syntax 

array_agg ( [ALL | DISTINCT] expr ) [FILTER ( WHERE cond ) ]

This function can also be invoked as a window function using the OVER clause.

Arguments

  • expr: An expression of any type.

  • cond: An optional boolean expression filtering the rows used for aggregation.

Returns

An ARRAY of the argument type.

The order of elements in the array is non-deterministic. NULL values are excluded.

If DISTINCT is specified the function collects only unique values and is a synonym for collect_set aggregate function.

Examples 

> SELECT array_agg(col) FROM VALUES (1), (2), (NULL), (1) AS tab(col);
 [1,2,1]
> SELECT array_agg(DISTINCT col) FROM VALUES (1), (2), (NULL), (1) AS tab(col);
 [1,2]