SQL self-referencing query. JOIN

self-reference, sql

Solution

You do this by joining the table to itself on the self-referencing column:

SELECT 
    u.unit_code, 
    u1.name + ' is a prerequisite of ' + u2.name AS unit_prerequisite 
FROM 
    units AS u1
    inner join units u2 on u2.RefId = u1.RefId

Problem

i need to query a self referencing relationship for unit prerequisites. i know that you need to use two Joins, do i SELECT my column and then join it to itself ? ``` SELECT u.unit_code, u.name + ' is a prerequisite of ' + u.name AS unit_prerequisite FROM units AS u ``` so far that is what i have, not sure where my joins have to be made? not even sure if that first part is correct.

Original source