Question

I need a help with what I believe is very trivial stuff.

class User {
    String name 
    static hasMany = [files : File]
}

class File {
    long size
}

Now when I need the total size of all files a given user has I use the following which is working :

def user = User.get(id)
user.files.each(total+=it.size)

but how ugly is it, when I am sure it can be done with simple select sum query with either plain SQL or GORM/CRITERIA

I have tried something like File.sumBySize..()

Or

def c = File.createCriteria()
def f = c.list{
    eq("user",  user)   // What here ?
    projections
        {
        sum("size")
        }
    }   

I dont know how to specify the parent(user) relationship which is not defined in File class but in Grails join tables

Any help appreciated

Answer 1

You can do it with an HQL query, but it has a small problem with the name of the ‘size’ field
(appears to be a reserved word). If you rename it to ‘length’, ‘fileSize’, etc. then this will work:

User.executeQuery(
   'select sum(file.length) from User u join u.files file where u.id=:userId',
   [userId: id])[0]