How to make MySql View Filter each table upon receipt

Question

I have a view that works like this:

CREATE VIEW v_myView as SELECT * FROM(
      (SELECT a,b,c,d FROM table1)
    UNION ALL
      (SELECT a,b,c,d FROM table2)
    UNION ALL
      (SELECT a,b,c,d FROM table3)
    .
    .
    .) 

When I use a view, I filter it like this:

SELECT * FROM v_myView WHERE a=x

While this works, it takes an hour (present hour, not figuratively). if I make such a request:

SELECT * FROM(
      (SELECT a,b,c,d FROM table1 WHERE a=x)
    UNION ALL
      (SELECT a,b,c,d FROM table2 WHERE a=x)
    UNION ALL
      (SELECT a,b,c,d FROM table3 WHERE a=x)
    .
    .
    .) 

it takes a minute. which made me wonder if there is a way to get MySql to do this automatically, which means the command WHEREwill work before each table is selected.

Answer 1

As you may already know, the second method is faster because, unlike the first, it does not display all the results from all three tables and then filters it.

(fooobar.com/questions/79067/...) , , .

:

( Int )

create function p1() returns INTEGER DETERMINISTIC NO SQL return @p1;

CREATE VIEW v_myView as SELECT * FROM(
      (SELECT a,b,c,d FROM table1 WHERE a=p1() )
    UNION ALL
      (SELECT a,b,c,d FROM table2 WHERE a=p1() )
    UNION ALL
      (SELECT a,b,c,d FROM table3 WHERE a=p1() )
    .
    .
    .) 

( 12 )

SELECT * FROM (select @p1:=12 p) parm, v_myView;