[英]SQL error Unknown column in field list using multiple subquery
我正在尝试根据列打印文本。 我的想法是将每个职业的所有计数结合起来,并用一个案例来展示它。 但我不确定这段代码有什么问题。 由于 sCount 不在字段列表中,因此出现错误。 任何帮助表示赞赏。
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;
你在尝试这样的事情吗:
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 ;
基于我的演示的结果将是:
总数
总共有5名医生。
共有7位歌手。
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