1. Specify a name for each field, which cannot be repeated.
2. You can create the field when you create it, or you can write the alias of the field in the select statement, and there can be no formula or the like.
For example:
Create? Opinion? View name?
As?
Choice? a.id,b.name? From where? A, b? Where is it? Aid or
Create? Opinion? View name? (ID card, name)?
be like
Choice? a.id,b.name? From where? A, b? Where is it? id=b.aid