Support lambda expressions

[apstndb]

Lambda expressions have not yet been supported.

Syntax

https://cloud.google.com/spanner/docs/reference/standard-sql/functions-reference#lambdas

(arg[, ...]) -> body_expression

arg -> body_expression

Examples

https://cloud.google.com/spanner/docs/reference/standard-sql/array_functions#array_filter

SELECT
  ARRAY_FILTER([1 ,2, 3], e -> e > 1) AS a1,
  ARRAY_FILTER([0, 2, 3], (e, i) -> e > i) AS a2;

/*-------+-------*
 | a1    | a2    |
 +-------+-------+
 | [2,3] | [2,3] |
 *-------+-------*/

https://cloud.google.com/spanner/docs/reference/standard-sql/array_functions#array_includes

SELECT
  ARRAY_INCLUDES([1, 2, 3], e -> e > 3) AS a1,
  ARRAY_INCLUDES([1, 2, 3], e -> e > 0) AS a2;

/*-------+------*
 | a1    | a2   |
 +-------+------+
 | false | true |
 *-------+------*/

https://cloud.google.com/spanner/docs/reference/standard-sql/array_functions#array_transform

SELECT
  ARRAY_TRANSFORM([1, 2, 3], e -> e + 1) AS a1,
  ARRAY_TRANSFORM([1, 2, 3], (e, i) -> e + i) AS a2;

/*---------+---------*
 | a1      | a2      |
 +---------+---------+
 | [2,3,4] | [1,3,5] |
 *---------+---------*/

Reference

https://cloud.google.com/spanner/docs/release-notes#March_21_2023

The following functions and expressions have been added to the GoogleSQL dialect:

• ARRAY_FILTER function
• ARRAY_TRANSFORM function
• Lambda expressions

FYI

• In spansql, they are developed, but not merged.
  • spanner/spansql: add support for ARRAY_FILTER, ARRAY_INCLUDES and ARRAY_TRANSFORM googleapis/google-cloud-go#8768
  • feat(spanner/spansql): add support for ARRAY_FILTER, ARRAY_INCLUDES and ARRAY_TRANSFORM googleapis/google-cloud-go#8769