Question

I have two tables with a 1:n relationship: "content" and "versioned-content-data" (for example, an article entity and all the versions created of that article). I would like to create a view that displays the top version of each "content".

I use this query (with a simple subquery):

SELECT     t1.id,     t1.title,     t1.contenttext,    t1.fk_idothertable    t1.version FROM mytable as t1 WHERE (version = (         SELECT MAX(version) AS topversion         FROM mytable         WHERE (fk_idothertable = t1.fk_idothertable))) 

The subquery is to the same table that extracts the highest version of a specific item. The versioned items will have the same fk_idothertable.

In SQL Server I tried to create an indexed view of this query but subqueries are not allowed in indexed views.

What is a way to convert this query to one with JOINs?

It seems like indexed views cannot contain:

• subqueries
• common table expressions
• derived tables
• HAVING clauses

Answer 1

This probably won’t help if table is already in production but the right way to model this is to make version = 0 the permanent version and always increment the version of OLDER material. So when you insert a new version you would say:

UPDATE thetable SET version = version + 1 WHERE id = :id INSERT INTO thetable (id, version, title, ...) VALUES (:id, 0, :title, ...) 

Then this query would just be

SELECT id, title, ... FROM thetable WHERE version = 0 

No subqueries, no MAX aggregation. You always know what the current version is. You never have to select max(version) in order to insert the new record.