SQL：如何按字母顺序排列工会？

Question

This is a slightly strange use case admittedly, but how do you order the results of a simple union like this alphabetically?

select name 
from Reviewer
union
select model
from Car; 

Answer 1

Ironically, in many databases, your query would return the values in alphabetical order. The sorting is done during the duplicate removal for union .

Of course, you can't depend on that. So, you should include an order by clause:

select name 
from Reviewer
union
select model
from Car
order by name;

The order by applies to the complete union . The column name comes from the first subquery.

Answer 2

select val
from (
  select name as val 
  from Reviewer

  union

  select model as val
  from Car
) as x
order by val

Answer 3

Here is how to set alias and ORDER BY :

SELECT 
  name AS NameModel
FROM Reviewer
UNION
SELECT  
  model AS NameModel
from Car
ORDER BY 
 NameModel;

The ORDER BY is evaluated after UNION .

Answer 4

your sql :

select name 
from Reviewer
union
select model
from Car;

Answer 1 :

select name from Reviewer
union
select model from Car
order by name;

Answer 2 :

select * from
    (select name "id" from Reviewer
    union
    select model from Car) x
order by x.id;

Answer 5

select val
from (
  select name as val 
  from Reviewer

  union

  select model as val
  from Car
) as x
order by val

My answer and above both are same. In SQL, we can write in different ways.

We can also ignore as operator.