Jaa

posexplode_outer table-valued generator function

  • Artikkeli

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

Returns rows by un-nesting the array with numbering of positions using OUTER semantics.

In Databricks Runtime 16.1 and above this function supports named parameter invocation.

Syntax

posexplode_outer(collection)

Arguments

  • collection: An ARRAY or MAP expression.

Returns

A set of rows composed of the position and the elements of the array or the keys and values of the map. The columns produced by posexplode_outer of an array are named pos and col. The columns for a map are called pos, key and value.

If collection is NULL, a single row with NULLs for the array or map values.

  • Applies to: check marked yes Databricks Runtime 12.1 and earlier:

    posexplode_outer can only be placed in the SELECT list as the root of an expression or following a LATERAL VIEW. When placing the function in the SELECT list there must be no other generator function in the same SELECT list or UNSUPPORTED_GENERATOR.MULTI_GENERATOR is raised.

  • Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime 12.2 LTS and above:

    Invocation from the LATERAL VIEW clause or the SELECT list is deprecated. Instead, invoke posexplode_outer as a table_reference.

Examples

Applies to: check marked yes Databricks Runtime 12.1 and earlier:

> SELECT posexplode_outer(array(10, 20)) AS elem, 'Spark';
 0  10 Spark
 1  20 Spark

> SELECT posexplode_outer(map(1, 'a', 2, 'b')) AS (num, val), 'Spark';
 0  1   a   Spark
 1  2   b   Spark

> SELECT posexplode_outer(array(1, 2)), posexplode_outer(array(3, 4));
  Error: UNSUPPORTED_GENERATOR.MULTI_GENERATOR

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime 12.2 LTS and above:

> SELECT pos, col FROM posexplode_outer(array(10, 20));
 0  10
 1  20

> SELECT pos, key, value FROM posexplode_outer(map(10, 'a', 20, 'b'));
 0  10   a
 1  22   b

> SELECT p1.*, p2.* FROM posexplode_outer(array(1, 2)) AS p1, posexplode_outer(array(3, 4)) AS p2;
 0  1  0  3
 0  1  1  4
 1  2  0  3
 1  2  1  4

-- Using lateral correlation in Databricks 12.2 and above
> SELECT p1.*, p2.* FROM posexplode_outer(array(1, 2)) AS p1, LATERAL posexplode_outer(array(3 * p1.col, 4 * p1.col)) AS p2;
 0      1  0  3
 0      1  1  4
 1      2  0  6
 1      2  1  8