[Bug]: Support SQL standard INTERVAL shorthand syntax `+ N days` in date arithmetic.

[Ariznawlll]

Is there an existing issue for the same bug?

• I have checked the existing issues.

Branch Name

main

Commit ID

e4637ad

Other Environment Information

- Hardware parameters:
- OS type:
- Others:

Actual Behavior

-- Standard SQL shorthand (currently NOT supported)
SELECT cast('2000-08-10' as date) + 30 days;

-- INTERVAL syntax (currently supported)
SELECT cast('2000-08-10' as date) + interval 30 day;

Expected Behavior

No response

Steps to Reproduce

as above

Additional information

No response

[fengttt]

This is not necessarily a standard syntax. We should just rewrite the query. Snowflake version just use
dateadd(day,30,to_date('2002-08-04'))

BTW, our syntax is GOOD. Interestingly, SELECT cast('2000-08-10' as date) + 30 days; actually runs in MySQL but the result is very weird, the result is a

days
20000840

FUBAR. We will NOT accept this behavior.

[fengttt]

Not our bug. @Ariznawlll please fix the query sql statements.