题解 | #别名#

select vend_id ,
vend_name as vname,
vend_address as vaddress,
vend_city as vcity
from Vendors
order by vname

1.考察给多个列取别名.

2.考察语句的执行顺序,order by语句执行在select之后,可以用别名,但是where在select之前,不可以使用别名进行过滤.