使用两个表的并集获取Count&ŧ039；s

Posted 2021-02-26

I was having the hardest time getting this to work. It's a collection of various items. For whatever reason, I needed to include the CASE statement due to NULL's coming back. If this helps you out... go for it.

EXAMPLE 1 -----
SELECT    Activity
        , COUNT (registrationID) AS totals
FROM
          (SELECT
                    CASE
                              WHEN r1.Activity0403_Winner <> 'Spa (50 minutes)'
                              THEN r1.Activity0403_Winner
                              ELSE r1.Activity0403_Winner + ' - ' + r1.Activity0403_WinnerSpaChoice + ' ~ ' + r1.Activity0403_WinnerSpaTime
                    END AS Activity
                  , r1.registrationID
          FROM      Registrations r1
          WHERE     r1.Activity0403_Winner IS NOT NULL
                AND
                    r1.Activity0403_Winner <> 'No Activity'
 
          UNION ALL
 
          SELECT
                    CASE
                              WHEN r2.Activity0403_Guest <> 'Spa (50 minutes)'
                              THEN r2.Activity0403_Guest
                              ELSE r2.Activity0403_Guest + ' - ' + r2.Activity0403_GuestSpaChoice + ' ~ ' + r2.Activity0403_GuestSpaTime
                    END AS Activity
                  , r2.registrationID
          FROM      Registrations r2
          WHERE     r2.Activity0403_Guest IS NOT NULL
                AND
                    r2.Activity0403_Guest <> 'No Activity'
          ) AS X (Activity, registrationID)
GROUP BY  X.Activity
ORDER BY  X.Activity;
 
 
EXAMPLE 2 -----
SELECT X.emp_id, COUNT(project_id) AS project_tot 
FROM (SELECT emp_id, project_id 
FROM DB1.Table1 
UNION 
SELECT emp_id, project_id 
FROM DB2.Table1) 
AS X(emp_id, project_id) 
GROUP BY X.emp_id;