Mysql VIEW在FROM条件中删除子查询

Question

im really newbie with my sql and im trying to create some views buts mysql yell with error

ERROR 1349 (HY000): View's SELECT contains a subquery in the FROM clause

how can i remove subquery in FROM condition and get the same results in a view?

SELECT actual, 
        curr, 
        CASE WHEN actual > anterior THEN 'raise' 
            WHEN actual < anterior THEN 'drop' ELSE 'nothing' 
        END as 'status' 
FROM ( 
        SELECT o.i_price as actual, o.i_currency as curr, 
            (
                SELECT i.i_price 
                FROM Info i 
                WHERE i.i_article_id = 1 
                  AND i.i_insert < o.i_insert 
                ORDER BY i.i_insert DESC LIMIT 1
            ) AS anterior 
        FROM Info o 
        WHERE o.i_article_id = 1 
        ORDER BY o.i_insert 
        DESC LIMIT 1 ) as q

Answer 1

You cannot use dinamica subquery during the creation of a view so you should create a proper view for subquery

    create view my_q as 
    SELECT o.i_price as actual, o.i_currency as curr, 
                (
                    SELECT i.i_price 
                    FROM Info i 
                    WHERE i.i_article_id = 1 
                      AND i.i_insert < o.i_insert 
                    ORDER BY i.i_insert DESC LIMIT 1
                ) AS anterior 
            FROM Info o 
            WHERE o.i_article_id = 1 
            ORDER BY o.i_insert 
            DESC LIMIT 1

and the call the view in your top view

    create  view my_top_view as  
    SELECT actual, 
            curr, 
            CASE WHEN actual > anterior THEN 'raise' 
                WHEN actual < anterior THEN 'drop' ELSE 'nothing' 
            END as 'status' 
    FROM  my_q;

With this the performance will suffer .. but to overcome the error you must not use subquery dynamics .. if you can is definitely better to rewrite the query .

Answer 2

View's select contains a subquery error: You can solve this. Use mysql mysqlworkbench to connect mysql DB. and run create view script from mysqlworkbench. It will work