What is this type of SELECT statement called?

[mrherman]

Hi -- I'd like to ask about the SQL statement below, which is something that I didn't know about: the second SELECT, after the FROM phrase.  My question is, what is this called?  Is it a NESTED SELECT, a SUB-SELECT, an EMBEDED SELECT, or what?  I want to read more on this type of statement, but don't know how to classify it.  Thanks!

 

SELECT t.* 
  FROM table1 t, 
  ( SELECT id 
      FROM table1 
     ORDER 
        BY id DESC 
     LIMIT 5,1 
  ) as x
WHERE t.id <= x.id
ORDER 
   BY RAND()
LIMIT 3

 

 

 

 

[MasterACE14]

Subquery.

[mrherman]

Well, that was simple enough.  I thought subqueries were always in the WHERE clause.  But I looked it up and you are right.  Very helpful.  Thanks!