collect_list aggregate function

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime

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

Syntax 

collect_list ( [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 collect_list(col) FROM VALUES (1), (2), (NULL), (1) AS tab(col);
 [1,2,1]

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