Contando el número de filas devuelto por una consulta de selección

Question

Necesito contar el número de filas que devuelve la consulta siguiente.

select m.Company_id 
from Monitor as m 
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id 
    group by m.Company_id 
    having COUNT(m.Monitor_id)>=5 

He tratado con el siguiente

select COUNT(*) from 
(
select m.Company_id 
from Monitor as m 
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id 
    group by m.Company_id 
    having COUNT(m.Monitor_id)>=5) 

Se da un mensaje de error en el analizador de consultas, que dice lo siguiente:

Msg 102, nivel 15, estado 1, línea 7 incorrecta sintaxis cerca de ')'.

Answer 1

SQL Server requiere subconsultas que SELECT FROM o JOIN que tiene un alias.

Añadir un alias a su subconsulta (en este caso x):

select COUNT(*) from 
(
select m.Company_id 
from Monitor as m 
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id 
    group by m.Company_id 
    having COUNT(m.Monitor_id)>=5) x 

Answer 2

select COUNT(*) 
from Monitor as m 
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id 
    group by m.Company_id 
    having COUNT(m.Monitor_id)>=5 

Answer 3

trate de envolver toda su selecto entre paréntesis, a continuación, ejecutar una cuenta (*) en la que

select count(*) 
from 
(
    select m.id 
    from Monitor as m 
    inner join Monitor_Request as mr 
     on mr.Company_ID=m.Company_id group by m.Company_id 
    having COUNT(m.Monitor_id)>=5 
) myNewTable 

Answer 4

La sintaxis el error se debe a que falta un alias para la subconsulta:

select COUNT(*) from 
(
select m.Company_id 
from Monitor as m 
    inner join Monitor_Request as mr on mr.Company_ID=m.Company_id 
    group by m.Company_id 
    having COUNT(m.Monitor_id)>=5) mySubQuery /* Alias */