How to count records in more than one table?

Question

I have these 3 tables:

I want to mount a SELECT that counts the number of records for each of them.

SELECT
   COUNT(client.idClient) AS clientQuantity,
   COUNT(clientVehicle.idClientVehicle) AS clientVehicle, 
   COUNT(parking.idParking) AS parkingQuantity 
FROM 
    client,
    clientVehicle,
    parking
WHERE
    client.idClient AND
    clientVehicle.idClientVehicle AND 
    parking.idParking

However, the result is 4 for all, and it should be, parkingQuantity 1, clientQuantity2 and clientVehicles 2. Where I’m wrong?

Thank you very much.

Answer 1

Just looking at her SELECT and what he tried to do in WHERE, which was supposed to be the JOIN between the tables, I can suggest this SELECT:

SELECT COUNT(client.idClient) AS clientQuantity, 
       COUNT(clientVehicle.idClientVehicle) AS clientVehicle, 
       COUNT(parking.idParking) AS parkingQuantity 
  FROM client
 INNER JOIN clientVehicle ON client.idClient = clientVehicle.idClient
 INNER JOIN parking ON parking.parkingPass = client.parkingPass

Note that in the table "Parking", supposedly the JOIN should be by the column "idParking", but by the photo of your model I did not identify relative column in any of the tables, so I did the JOIN by "parkingPass"

Answer 2

I found a solution

SELECT  (
    SELECT COUNT(*)
    FROM   client
    ) AS qttClient,
    (
    SELECT COUNT(*)
    FROM   parking
    ) AS qttParking,
    (
    SELECT COUNT(*)
    FROM   clientVehicle
    ) AS qttClientVehicle
FROM    dual

Answer 3

Enjoying the friend’s select already published in the post, you can replace the * by the numerical position of the column you want to count, in these cases where you want the ID columns that are the first the answer is as follows:

SELECT ( SELECT COUNT(1) FROM client ) AS qttClient, ( SELECT COUNT(1) FROM Parking ) AS qttParking, ( SELECT COUNT(1) FROM clientVehicle ) AS qttClientVehicle FROM dual