标准 SQL (BigQuery) 中的用户定义数据类型？

Question

Is it possible to create user defined data types in standard SQL, which can then be referenced from within the SQL code itself?

As an example, let's say I wanted to create a function that would take two instances of STRUCT - each containing three entries of type STRING . This would require writing something like this;

CREATE TEMP FUNCTION myFunc(x STRUCT<STRING, STRING, STRING>, y STRUCT<STRING, STRING, STRING>) AS (...);

What I want to do though, is something like this (pseudo-code);

CREATE TYPE myType STRUCT<STRING, STRING, STRING>
CREATE TEMP FUNCTION myFunc(x myType, y myType) AS (...)

Answer 1

Something similar would be using ANY TYPE to create your function like:

CREATE TEMP FUNCTION myFunc(x ANY TYPE, y ANY TYPE) AS (...);

To answer question in comments, if strong type check is needed, you can still do something like this and use to check parameter of myFunc() to report an error if type is incompatible:

CREATE TEMP FUNCTION check_type_x(x ANY TYPE) AS (STRUCT(x.a, x.b, x.c));


SELECT myFunc(check_type_x(col1), check_type_x(col2));