mySQL：从另一个表中选择一个count（*）？

Question

I have two tables: 1 Table wccrm_orders where all orders are stored, and a table wccrm_kunden where all the user data is stored. In wccrm_orders, I have a date-field "ordered_date" and in wccrm_kunden a date-field "Anprobe"

When I want to select the wccrm_orders I use that code:

Select Year(wccrm_orders.ordered_date) as Jahr,
Month(wccrm_orders.ordered_date) as Monat, round(sum(wccrm_orders.preis)) as Summe, 
count(*) as Anzahl from wccrm_orders 
GROUP BY YEAR(wccrm_orders.ordered_date), MONTH(wccrm_orders.ordered_date)

When I want to count(*) all the appointments from wccrm_kunden.anprobe I use this code:

Select Year(wccrm_kunden.anprobe) as Jahr, Month(wccrm_kunden.anprobe) as
Monat, count(*) as Anzahl from wccrm_kunden where wccrm_kunden.status = 1 
GROUP BY YEAR(wccrm_kunden.anprobe), MONTH(wccrm_kunden.anprobe)

How can I combine these codes? How can I achieve it, to get the numbers of trials (appointments) into the first SELECT?

Thank you very much for your help!

BR,

Stefan

Answer 1

A couple of sub-queries may work:

SELECT A.Jahr, A.Monat, A.Summe, A.Anzahl, B.AnzahlB
FROM 
    (SELECT Year(wccrm_orders.ordered_date) as Jahr,
       Month(wccrm_orders.ordered_date) as Monat,
       round(sum(wccrm_orders.preis)) as Summe, 
       count(*) as Anzahl 
    FROM   wccrm_orders 
    GROUP BY
       YEAR(wccrm_orders.ordered_date),
       MONTH(wccrm_orders.ordered_date)) AS A
    LEFT OUTER JOIN
    (SELECT Year(wccrm_kunden.anprobe) as Jahr,
        Month(wccrm_kunden.anprobe) as Monat,
        count(*) as AnzahlB
    FROM wccrm_kunden 
    WHERE wccrm_kunden.status = 1 
    GROUP BY 
        YEAR(wccrm_kunden.anprobe),
        MONTH(wccrm_kunden.anprobe)) AS B
    ON A.Jahr = B.Jahr AND A.Monat = B.Monat

(Sorry, don't have the schema for this DB, so there may be a syntax error (or three!) in this code, but hopefully you get the idea.)