SQL error Unknown column in field list using multiple subquery-CodePudding

I'm trying to print the text based on the column. My idea was union all the count on each occupation and use a case to display it. But I'm not sure what is wrong with this code. Getting a error as sCount is not in field list. Any help is appreciated.

SELECT  CASE

        WHEN Occupation = "doctor" THEN
        CONCAT("There are a total of ", dCount, " " , Occupation, "s.")
        
        WHEN Occupation = "singer" THEN
        CONCAT("There are a total of ", sCount, " " , Occupation, "s.")
        
        END
FROM (
    SELECT * FROM (
        SELECT COUNT(Occupation) AS dCount, Lower(Occupation) AS Occupation FROM OCCUPATIONS WHERE Occupation = 'Doctor'
    UNION
        SELECT COUNT(Occupation) AS sCount, Lower(Occupation) AS Occupation FROM OCCUPATIONS WHERE Occupation = 'Singer'
    ) AS s
) AS m;

// this didnt work either
SELECT  CASE

        WHEN Occupation = "doctor" THEN
        CONCAT("There are a total of ", dCount, " " , Occupation, "s.")
        
        WHEN Occupation = "singer" THEN
        CONCAT("There are a total of ", sCount, " " , Occupation, "s.")
        
        END
FROM (
    SELECT COUNT(Occupation) AS dCount, Lower(Occupation) AS Occupation FROM OCCUPATIONS WHERE Occupation = 'Doctor'
    UNION
    SELECT COUNT(Occupation) AS sCount, Lower(Occupation) AS Occupation FROM OCCUPATIONS WHERE Occupation = 'Singer'
) AS m;

CodePudding user response：

Are you trying something like this :

CREATE TABLE OCCUPATIONS  (
  Occupation varchar(100) );

INSERT INTO OCCUPATIONS  VALUES ('doctor'),('doctor'),
                                ('singer'),('singer'),
                                ('doctor'),('doctor'),
                                ('singer'),('singer'),
                                ('doctor'),('singer'),
                                ('singer'),('singer');




SELECT  CASE
        WHEN Occupation = "doctor" THEN
        CONCAT("There are a total of ", tbl.dCount, " " , Occupation, "s.") 
        WHEN Occupation = "singer" THEN
        CONCAT("There are a total of ", tbl.sCount, " " , Occupation, "s.")        
        END as total_count
FROM (          
SELECT COUNT(Occupation) AS dCount,null as sCount, Lower(Occupation) AS Occupation 
FROM OCCUPATIONS 
WHERE Occupation = 'doctor'
group by Occupation 
union 
SELECT null as tst, COUNT(Occupation) AS sCount, Lower(Occupation) AS Occupation 
FROM OCCUPATIONS 
WHERE Occupation = 'singer'
group by Occupation 
      )
as tbl ;

Result based on my demo would be:

total_count

There are a total of 5 doctors.

There are a total of 7 singers.

Demo: https://www.db-fiddle.com/f/pB6b5xrgPKCivFWcpQHsyE/28