爲什麼我的查詢在添加SUM函數後失敗？

Question

下面的查詢按預期執行，給我定的字段被查詢

SELECT 1 as SEQ, TERM_DESC as TERM, PRIMARY_COLLEGE_DESC as COLLEGE, LEVEL_GROUPING_CODE as  LEVEL_CODE, LEVEL_GROUPING_DESC as LEVEL_DESC 
FROM SECopy as SE 

然而預期的輸出，當我添加函數SUM（）在現場，我收到有關TERM_DESC以下錯誤，它甚至與使用SUM（）函數的ID_COUNT沒有關係。

SELECT 1 as SEQ, TERM_DESC as TERM, PRIMARY_COLLEGE_DESC as COLLEGE, LEVEL_GROUPING_CODE as  LEVEL_CODE, LEVEL_GROUPING_DESC as LEVEL_DESC, SUM(ID_COUNT) as HEADCOUNT 
from SECopy as se 

，我發現了以下錯誤：

Column 'Student_Enrollment_copy.TERM_DESC' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. 

爲什麼會加入SUM（）函數後才失敗？

Answer 1

1. 別名
2. 你應該使用在集團所有列BY子句除了聚合函數

SELECT 1 as SEQ, 
TERM_DESC as TERM, 
PRIMARY_COLLEGE_DESC as COLLEGE, 
LEVEL_GROUPING_CODE as  LEVEL_CODE, 
SUM(ID_COUNT) as HEADCOUNT 
from SECopy 
GROUP BY TERM_DESC,PRIMARY_COLLEGE_DESC,LEVEL_GROUPING_CODE 

Answer 2

您需要將您的SELECT語句中的所有字段粘貼到GROUP BY子句中，但不會被SUM（），AVG（），MIN（）等聚合。

SELECT 
    1 AS SEQ, 
    TERM_DESC AS TERM, 
    PRIMARY_COLLEGE_DESC AS COLLEGE, 
    LEVEL_GROUPING_CODE AS LEVEL_CODE, 
    LEVEL_GROUPING_DESC AS LEVEL_DESC, 
    SUM(ID_COUNT) AS HEADCOUNT 
FROM SECopy AS se 
GROUP BY 
    TERM_DESC, PRIMARY_COLLECT_DESC,LEVEL_GROUPING_CODE,LEVEL_GROUPING_DESC 

不需要對錶

Answer 3

您需要爲查詢添加分組標準。

在SQL服務器（和許多其他SQL的RDBMS），需要分組列的定義聚合函數：

select ...., sum(...) ... -- Fields, expresions and (aggregate) functions 
from your_table -- and/or data sources 
-- any where conditions 
group by ... --- Grouping criteria 

Answer 4

根據您的實際需求，你可能會尋找

SELECT 
    1 as SEQ 
    , TERM_DESC as TERM 
    , PRIMARY_COLLEGE_DESC as COLLEGE 
    , LEVEL_GROUPING_CODE as LEVEL_CODE 
    , LEVEL_GROUPING_DESC as LEVEL_DESC 
    , (SELECT SUM(ID_COUNT) FROM SECOPY) as HEADCOUNT 
from SECopy