Why does “select count(*)” from nothing return 1

Question

With SQL Server 2012 :

use master
select *

yields

Must specify table to select from

which is

Answer 1

SQL Server is (behind the curtain) effectively applying a from to a dummy table, which has only one row. Thus you will get 1 for your count.

select 'test'

will do the same thing, as an example, return 'test' one time.

It's like the DUAL table in Oracle, SYSDUMMY1 in DB2, etc.

As requested, here's a couple of links to MS Connect on this topic:

Clicky

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