[storm] Query using count

[Gustavo Niemeyer]

akira wrote:
> Could someone help out? I still have´nt found a solution. I posted the 
> whole query that I would like to replicate, maybe it got mixed up on the 
> forum. Well here it is again:
> 
> SELECT Link,
>          COUNT(*)-1 AS level
>     FROM tree AS node,
>          tree AS parent
>    WHERE node.lft BETWEEN parent.lft AND parent.rgt
> GROUP BY node.lft
> ORDER BY node.lft;
> 
> I have created aliases like this:
> 
> parent = ClassAlias(Link)
> node = ClassAlias(Link)

This is the equivalent expression:

    columns = (parent.link, Count(*)-1)
    where = And(node.lft >= parent.lft, node.lft <= parent.rgt)
    expr = Select(columns, where, order_by=node.lft, group_by=node.lft)

> this is how far I got
> 
> rows = store.find((node, parent), node.lft > parent.lft, node.lft < parent.rgt)

As we discussed in the other thread, the group_by feature in the store is
designed but not yet implemented.

-- 
Gustavo Niemeyer
http://niemeyer.net