Explanation/Reference:
Explanation:
Subquery1: common table expression (CTE)
A common table expression (CTE) can be thought of as a temporary result set that is defined within the execution scope of a single SELECT, INSERT, UPDATE, DELETE, or CREATE VIEW statement. A CTE is similar to a derived table in that it is not stored as an object and lasts only for the duration of the query.
Unlike a derived table, a CTE can be self-referencing and can be referenced multiple times in the same query.
Subquery2: global temporary table
Global temporary tables are visible to any user and any connection after they are created, and are deleted when all users that are referencing the table disconnect from the instance of SQL Server.
Subquery3: local temporary table
Local temporary tables are visible only to their creators during the same connection to an instance of SQL Server as when the tables were first created or referenced. Local temporary tables are deleted after the user disconnects from the instance of SQL Server.
References:
https://technet.microsoft.com/en-us/library/ms190766(v=sql.105).aspx
https://technet.microsoft.com/en-us/library/ms186986.aspx