SQL：聚合函数或 GROUP BY

Question

以下是我收到的一条 sql 语句和一个错误。我已经包含了两个表中所有可能的字段，有什么问题？我想按 prodID 对所有返回的项目进行分组

选择列表中的“orders.adminStatus”列无效，因为它既不包含在聚合函数中，也不包含在 GROUP BY 子句中

 SELECT TOP 20 
         ADMINSTATUS,   CURRENCY,   CUSTOMERID,     CUSTOMERMESSAGE,    DELTIME,    DELTOTAL,   DISCOUNT,   DISCOUNTCODE,   
         IP,    ITEMDES,    OPTIONS,    ORDEREDID,  ORDERTOTAL,
         oi.ORDER_ID,   o.ORDER_ID,     PAYMENTTYPE,    PPRICE,     PRODID,     QTY,    REASON,     SECURITYKEY,    SHIPADDRESS1,   
         SHIPADDRESS2,  SHIPADDRESS3,   SHIPCITY,   SHIPCOMPANY,    
         SHIPCOUNTRY,   SHIPCOUNTY,     SHIPMETHOD,
         SHIPNAME,  SHIPPOSTCODE,   STATUS,     STOCKCODE,  SUBTOTAL,   TAX,    TAXABLE,    TIMEDATE,   TXAUTHNO,   VENDORTXCODE,   VPSTXID
         FROM orderedItems oi
         left join orders o on  oi.order_id = o.order_id


    Group by PRODID

Answer 1

因为，正如它所说，如果您使用 GROUP BY，您要么需要按要返回的字段进行分组，要么对其应用聚合函数；例如：最大值、最小值等

SELECT TOP 20  
         ADMINSTATUS,   CURRENCY,   CUSTOMERID,     CUSTOMERMESSAGE,    DELTIME,    DELTOTAL,   DISCOUNT,   DISCOUNTCODE,    
         IP,    ITEMDES,    OPTIONS,    ORDEREDID,  ORDERTOTAL, 
         oi.ORDER_ID,   o.ORDER_ID,     PAYMENTTYPE,    PPRICE,     PRODID,     QTY,    REASON,     SECURITYKEY,    SHIPADDRESS1,    
         SHIPADDRESS2,  SHIPADDRESS3,   SHIPCITY,   SHIPCOMPANY,     
         SHIPCOUNTRY,   SHIPCOUNTY,     SHIPMETHOD, 
         SHIPNAME,  SHIPPOSTCODE,   STATUS,     STOCKCODE,  SUBTOTAL,   TAX,    TAXABLE,    TIMEDATE,   TXAUTHNO,   VENDORTXCODE,   VPSTXID 
         FROM orderedItems oi 
         left join orders o on  oi.order_id = o.order_id 



Group by          ADMINSTATUS,   CURRENCY,   CUSTOMERID,     CUSTOMERMESSAGE,    DELTIME,    DELTOTAL,   DISCOUNT,   DISCOUNTCODE,    
     IP,    ITEMDES,    OPTIONS,    ORDEREDID,  ORDERTOTAL, 
     oi.ORDER_ID,   o.ORDER_ID,     PAYMENTTYPE,    PPRICE,     PRODID,     QTY,    REASON,     SECURITYKEY,    SHIPADDRESS1,    
     SHIPADDRESS2,  SHIPADDRESS3,   SHIPCITY,   SHIPCOMPANY,     
     SHIPCOUNTRY,   SHIPCOUNTY,     SHIPMETHOD, 
     SHIPNAME,  SHIPPOSTCODE,   STATUS,     STOCKCODE,  SUBTOTAL,   TAX,    TAXABLE,    TIMEDATE,   TXAUTHNO,   VENDORTXCODE,   VPSTXID 

Answer 2

如果您选择单独的列，则它们都需要出现在 GROUP BY 子句中，除非它们是聚合函数。

请看这里：http://msdn.microsoft.com/en-us/library/ms177673.aspx

例如

SELECT TOP 20 
         ADMINSTATUS,   CURRENCY,   CUSTOMERID,     CUSTOMERMESSAGE,    DELTIME,    DELTOTAL,   DISCOUNT,   DISCOUNTCODE,   
         IP,    ITEMDES,    OPTIONS,    ORDEREDID,  ORDERTOTAL,
         oi.ORDER_ID,   o.ORDER_ID,     PAYMENTTYPE,    PPRICE,     PRODID,     QTY,    REASON,     SECURITYKEY,    SHIPADDRESS1,   
         SHIPADDRESS2,  SHIPADDRESS3,   SHIPCITY,   SHIPCOMPANY,    
         SHIPCOUNTRY,   SHIPCOUNTY,     SHIPMETHOD,
         SHIPNAME,  SHIPPOSTCODE,   STATUS,     STOCKCODE,  SUBTOTAL,   TAX,    TAXABLE,    TIMEDATE,   TXAUTHNO,   VENDORTXCODE,   VPSTXID
         FROM orderedItems oi
         left join orders o on  oi.order_id = o.order_id


    Group by ADMINSTATUS,   CURRENCY,   CUSTOMERID,     CUSTOMERMESSAGE,    DELTIME,    DELTOTAL,   DISCOUNT,   DISCOUNTCODE,   
         IP,    ITEMDES,    OPTIONS,    ORDEREDID,  ORDERTOTAL,
         oi.ORDER_ID,   o.ORDER_ID,     PAYMENTTYPE,    PPRICE,     PRODID,     QTY,    REASON,     SECURITYKEY,    SHIPADDRESS1,   
         SHIPADDRESS2,  SHIPADDRESS3,   SHIPCITY,   SHIPCOMPANY,    
         SHIPCOUNTRY,   SHIPCOUNTY,     SHIPMETHOD,
         SHIPNAME,  SHIPPOSTCODE,   STATUS,     STOCKCODE,  SUBTOTAL,   TAX,    TAXABLE,    TIMEDATE,   TXAUTHNO,   VENDORTXCODE,   VPSTXID

Answer 3

由于您是按 PRODID 分组的，因此在选择列表中应该只存在 PRODID，如果您想要选择列表中的任何其他列，则应该使用聚合函数，如 AVG()、MIN() MAX() 等..

如果按表中所有可用列分组，则等于

select distinct * from table

通常 GROUP BY 与聚合函数一起使用以获取表中每个组的 MIN、MAX 等

GROUP BY examples