Batch delete in #grails

delete1.groovy

groupsToDelete = [] 
Group.list().each { group -> 
  if(group.members.isEmpty()) 
    groupsToDelete << link
} 
groupsToDelete*.delete() 

delete2.groovy

Group.where { 
  members.size() == 0 
}.deleteAll()

delete3.groovy

import grails.gorm.*

def criteria = new DetachedCriteria(Group).build { 
  isEmpty 'members'
}
criteria.deleteAll()
// criteria.count()

domains.groovy

class Group {
  String name
  
  static hasMany = [members : Member]
}

class Member {
  String name
}