Can't get the view I want : MySQL

Question

I have some question about create Mysql view.

Table:

      ID  name  num
      1   ccc    3
      1   bbb    4
      1   aaa    2

query:"SELECT ID,name,num FROM (SELECT * FROM test ORDER BY ID,num DESC) AS A GROUP BY ID;"

Result:

       1    bbb 4

This result is what I want.

query:

"CREATE VIEW I AS SELECT * FROM test ORDER BY ID,num DESC,`name`;
CREATE VIEW T AS SELECT ID,name,num FROM I GROUP BY ID;"

VIEW T:

       1    aaa 2

How can I make VIEW T is same as query result?

Answer 1

One way to phrase this query is to join to a subquery which finds the maximum number values for each ID:

CREATE VIEW T AS
SELECT
    t1.ID, t1.name, t1.num
FROM test t1
INNER JOIN
(
    SELECT ID, MAX(num) AS max_num
    FROM test
    GROUP BY ID
) t2
    ON t1.ID  = t2.ID      AND
       t1.num = t2.max_num

Answer 2

Well use the same select query in your view statement

create view T as
SELECT ID,name,num 
FROM (SELECT * FROM test ORDER BY ID,num DESC) AS A 
GROUP BY ID;

Finally, you can't create view from a view and thus the below statement is invalid

create view T as
select * from I; --I is a view