sql - What is SELF JOIN and when would you use it? - Stack Overflow
Jun 13, 2024 · You use a self join when a table references data in itself. E.g., an Employee table may have a SupervisorID column that points to the employee that is the boss of the current …
sql - Explanation of self-joins - Stack Overflow
Mar 16, 2010 · A self join is a join of a table with itself. A common use case is when the table stores entities (records) which have a hierarchical relationship between them.
sql - Self join vs. inner join - Stack Overflow
Aug 10, 2015 · SQL, of course, can accomplish this in one query using, you guessed it, a SELF JOIN. What really triggers the need for a SELF JOIN here is that the table contains a unique …
sql - Purpose of Self-Joins - Stack Overflow
Apr 20, 2017 · Self-joins are useful whenever a table contains a foreign key into itself. An employee has a manager, and the manager is... another employee. So a self-join makes …
sql - Self Join to get employee manager name - Stack Overflow
Jul 11, 2012 · Emp_id, Emp_Name and Mgr_id. I am trying to create a view which will list Emp_id, Emp_name, Mgr_id and Mgr_name (by cross joining the Employee table). I tried outer join, …
sql - Self-join of a subquery - Stack Overflow
May 25, 2009 · I was wondering, is it possible to join the result of a query with itself, using PostgreSQL?
sql - Simplest way to do a recursive self-join? - Stack Overflow
What is the simplest way of doing a recursive self-join in SQL Server? PersonID | Initials | ParentID 1 CJ NULL 2 EB 1 3 MB 1 4 SW ...
What is a SQL JOIN, and what are the different types?
Self-Join:: A customized behavior of join where a table combined with itself; This is typically needed for querying self-referencing tables (or Unary relationship entity).
Self-join excluding joining a row to itself - Stack Overflow
Dec 18, 2024 · They have identical values but nonetheless are separate rows and SQL does sometimes let you treat them separately (for example with set rowcount 1 update #a set x = 40 …
sql - When do we need self join exactly? - Stack Overflow
May 13, 2015 · I am new to SQL. I know only basic queries but not in depth. I searched for Self join necessary and i found this question Most of the answer says it is useful for referencing the …