How do MySQL views work?

Question

When I create a view I am basically making a new table that will automatically be transacted upon when data in one of the tables it joins changes; is that correct?

A

Answer 1

I ran into the same problem also (to my surprise, because my search seems to indicate that Oracle and MS do support it).

I get around this limitation (at least for now, until proven non-usable) by creating two additional views for my final view.

Example:

CREATE VIEW Foo1 AS
    SELECT * FROM t ORDER BY ID, InsertDate DESC

CREATE VIEW Foo2 AS
    SELECT * FROM Foo1 GROUP BY ID

CREATE VIEW Foo AS
    SELECT * FROM Foo2 ORDER BY ID

The example above basically has a table 't' which is a temporal table containing all the revisions. My 'Foo' (view) basically is a simple view of only my most current revisions of each record. Seems to work alright for now!

Update:

I don't know if this is another bug in MySQL 5.1, but the above example doesn't in fact work! The 'Foo1' works as expected, but the 'Foo2' seems to ignore the order prior to grouping so my end result is not what is intended. I even get the same result if I change the 'DESC' for 'ASC' (surprisingly).

Also, if you read the 17.5.1. View Syntax section, it clearly states:

"A view can be created from many kinds of SELECT statements. It can refer to base tables or other views. It can use joins, UNION, and subqueries."

I'm going to update my database to 5.6 and try it again!