Module 1: Basics and Background
Lecture 2: Advanced Database Queries
Join
Join
:
Given two databases
,
, a distance function
and range
or number of nearest neighbours
, return object pairs
such that
satisfy
or
conditions
and
conditions are defined similar to range and
kNN
searches
If
and
are same, then the problem becomes
self-join
Problem can be defined over
m
databases
A general
"distance"
function
is defined
Answer set
contains
m
-tuplets of the form
,
, a distance function 
and range 
or number of nearest neighbours 
, return object pairs
such that 
satisfy 
is defined
contains m-tuplets of the form