Question

I want to count the number of interface down and up and write this code that count them from two tables Nodes and Interface. This code works but I want to know any other way or optimize of this code? what is the best way to count them?

       SELECT
    q1.NodeName,
    q1.Nup as up, 
    q2.ndown as down
   FROM (
    SELECT
        Nodes.NodeID AS NodeID,
        Interfaces.NodeID AS InterfaceID,
        Nodes.Caption AS NodeName,
        Interfaces.Status as Status,
        Count(Nodes.Caption) as Nup 
        FROM 
        Nodes INNER JOIN Interfaces ON (Nodes.NodeID = Interfaces.NodeID)
        WHERE  
        (
          (
           (Interfaces.Status = '2'))
        )
        GROUP BY  Nodes.NodeID, Nodes.Caption, Interfaces.Status, Interfaces.NodeID
    ) AS q1
    INNER JOIN (
SELECT   
Interfaces.NodeID AS InterfaceID,
Nodes.Caption AS NodeName,
Interfaces.Status as Status,
Count(Nodes.Caption) as ndown
FROM 
Nodes INNER JOIN Interfaces ON (Nodes.NodeID = Interfaces.NodeID)
WHERE  
(
  (
   (Interfaces.Status = '1'))
)

GROUP BY  Nodes.NodeID, Nodes.Caption, Interfaces.Status, Interfaces.NodeID

   ) AS q2

 ON (q1.NodeID = q2.InterfaceID)
order by down Desc

Answer 1

You can combine the queries:

SELECT
    Nodes.Caption AS NodeName,
    Count(
      CASE WHEN Interfaces.Status = '2'
        THEN 1 
        ELSE NULL 
      END) as up,
    Count(
      CASE WHEN Interfaces.Status = '1'
        THEN 1 
        ELSE NULL 
      END) as down
FROM Nodes 
  INNER JOIN Interfaces ON (Nodes.NodeID = Interfaces.NodeID)
WHERE Interfaces.Status IN('1', '2')
GROUP BY  Nodes.NodeID, Nodes.Caption
order by 3 Desc

Note: in your original query, if a interface is always up, or always down, it would not show up in the resultset since you were using a INNER JOIN.