选择多个列但group by应该只在一列上

Question

SELECT * FROM(SELECT DISTINCT DRUG_NAME, SUM(WEIGHT) FROM FIR

              INNER JOIN USER_LOGIN ON FIR.USER_ID = USER_LOGIN.USER_ID
              INNER JOIN POLICE_STATION ON FIR.PS_ID = POLICE_STATION.PS_ID
              INNER JOIN DRUG_INFO ON FIR.FIR_NO = DRUG_INFO.FIR_NO

              WHERE WEIGHT != 0 AND DRUG_FORM = 'Litres (l)'
              GROUP BY DRUG_NAME
              )

我希望在drug_name上有一个小组，但希望选择drug_form,weight,picture,username中的这些列。上面的sql语句工作正常但我无法选择drug_form,weight,picture,username列。

我想将像鸦片这样的药物名称合并在一起，并在1列上显示总数。

Answer 1

任何不在group by子句中的列都必须使用聚合函数（MAX，AVG，SUM等）。因为你是＆＃34;分组＆＃34;将多个值放入单个列中，您需要某种方法将数据压缩为单个值。

将其他列放入您的组中，或使用聚合函数。

Answer 2

如果您尝试这样做（未经测试）

SELECT d.drug_form,
d.weight,
ull.picture,
ull.username,
x.DRUG_NAME,
x.TotalWeight
FROM DRUG_INFO d inner join FIR f
on d.FIR_NO = f.FIR_NO
inner join USER_LOGIN ull
on f.USER_ID = ull.USER_ID
inner join
(SELECT DRUG_NAME,
 SUM(WEIGHT) as TotalWeight 
 FROM DRUG_INFO    
 WHERE WEIGHT != 0 
 AND DRUG_FORM = 'Litres (l)'
 GROUP BY DRUG_NAME
 ) x
on d.DRUG_NAME = x.DRUG_NAME