Using initcap function in materialized view fails

[BillBishop]

This query works:

select order_date, initcap(customer_name), count(*) AS number_of_orders

from ...

The initcap does as advertised and capitalizes the customer_name column.

However, if I wrap the same exact select in a create materialized view I get an error:

create or replace materialized view <my-view-name>

as

select order_date, initcap(customer_name), count(*) AS number_of_orders

from...

[DELTA_INVALID_CHARACTERS_IN_COLUMN_NAMES] Found invalid character(s) among ' ,;{}()\n\t=' in the column names of your schema. Invalid column names: initcap(customer_name). Please use other characters and try again. Alternatively, enable Column Mapping to keep using these characters.

Can you explain the difference?

[BillBishop · Accepted solution]

NOTE: I got it to work by aliasing the customer_name column, it's documented here: https://docs.databricks.com/aws/en/sql/language-manual/sql-ref-syntax-ddl-create-materialized-view#l...

However, it wasn't clear that "Non-column reference expressions require an alias" applies to ALL functions, not just  aggregate functions like the example.