This section describes functions and operators for examining and manipulating nested values. There are three nested data types: lists, structs, and maps.

List Functions

In the descriptions, l is the three element list [4, 5, 6].

Struct Functions

Map Functions

Range Functions

The functions range and generate_series create a list of values in the range between start and stop. The start parameter is inclusive. For the range function, the stop parameter is exclusive, while for generate_series, it is inclusive.

Based on the number of arguments, the following variants exist:

• range(start, stop, step)
• range(start, stop)
• range(stop)
• generate_series(start, stop, step)
• generate_series(start, stop)
• generate_series(stop)

The default value of start is 0 and the default value of step is 1.

SELECT range(5);
-- [0, 1, 2, 3, 4]

SELECT range(2, 5);
-- [2, 3, 4]

SELECT range(2, 5, 3);
-- [2]

SELECT generate_series(5);
-- [0, 1, 2, 3, 4, 5]

SELECT generate_series(2, 5);
-- [2, 3, 4, 5]

SELECT generate_series(2, 5, 3);
-- [2, 5]

Date ranges are also supported:

SELECT * FROM range(date '1992-01-01', date '1992-03-01', interval '1' month);

┌─────────────────────┐
│        range        │
├─────────────────────┤
│ 1992-01-01 00:00:00 │
│ 1992-02-01 00:00:00 │
└─────────────────────┘

List Aggregates

The function list_aggregate allows the execution of arbitrary existing aggregate functions on the elements of a list. Its first argument is the list (column), its second argument is the aggregate function name, e.g. min, histogram or sum.

SELECT list_aggregate([1, 2, -4, NULL], 'min');
-- -4

SELECT list_aggregate([2, 4, 8, 42], 'sum');
-- 56

SELECT list_aggregate([[1, 2], [NULL], [2, 10, 3]], 'last');
-- [2, 10, 3]

The following is a list of existing rewrites. Rewrites simplify the use of the list aggregate function by only taking the list (column) as their argument. list_avg, list_var_samp, list_var_pop, list_stddev_pop, list_stddev_samp, list_sem, list_approx_count_distinct, list_bit_xor, list_bit_or, list_bit_and, list_bool_and, list_bool_or, list_count, list_entropy, list_last, list_first, list_kurtosis, list_min, list_max, list_product, list_skewness, list_sum, list_string_agg, list_mode, list_median, list_mad and list_histogram.

SELECT list_min([1, 2, -4, NULL]);
-- -4

SELECT list_sum([2, 4, 8, 42]);
-- 56

SELECT list_last([[1, 2], [NULL], [2, 10, 3]]);
-- [2, 10, 3]

generate_subscripts

The generate_subscript(arr, dim) function generates indexes along the dimth dimension of array arr.

SELECT generate_subscripts([4,5,6], 1) AS i;
┌───┐
│ i │
├───┤
│ 1 │
│ 2 │
│ 3 │
└───┘

Related Functions

There are also aggregate functions list and histogram that produces lists and lists of structs.