`[ ]` (bracket sign) operator

Applies to: Databricks SQL Databricks Runtime

Returns an array element or map value given an index or key.

Syntax

expr [ keyExpr ]

Note that the use of brackets here is as literal text and not indicating optional syntax.

expr: An ARRAY or MAP expression.
keyExpr: If expr is an ARRAY an integral numeric. Otherwise an expression matching the type of the key of the MAP.

The result type is the element type of the ARRAY or the value type of the MAP.

The first element of an ARRAY is at index 0.

If the keyExpr is not a valid key for the MAP expr Databricks returns null.

If the keyExpr is out of bound for the ARRAY expr Databricks raises a INVALID_ARRAY_INDEXerror.

note

In Databricks Runtime, if spark.sql.ansi.enabled is false, the operator returns NULL instead of an out of bounds error.

SQL
> SELECT a[2] FROM VALUES(array(10, 20, 30)) AS T(a);
  30

> SELECT m[1] FROM VALUES(map(1, 'Hello', 2, 'World')) AS T(m);
  Hello