带别名的GROUP BY子句？

Question

有谁知道为什么我无法TotalSales在此查询中进行分组,如果是,我该如何解决此问题:

select coalesce(Author_ID, 'All Authors') as Author_ID
, case when Author_ID  is null then ' ' else coalesce(Book_ID, 'All Books') end as Book_ID
, TotalQuantity  
, coalesce(TotalSales, 'No Sales') as TotalSales   
from (    
     select  author_id as Author_ID 
            , book_id as Book_ID
            ,  sum(quantity) as TotalQuantity  
            ,  sum(quantity * order_price) as TotalSales   
            from a_bkinfo.book_authors   
            join a_bkorders.order_details using (book_id)
            where author_sequence = 1           
            group by Author_id, Book_ID, TotalSales with rollup
     ) tbl;

当作者没有图书销售时,我想在TotalSales下包含"无销售".这是更新版本.我不肯定它是正确的,但我确实有输出,似乎解决了这个问题.这里是:

select coalesce(Author_ID, 'All Authors') as Author_ID
, case when Author_ID is null then ' ' else coalesce(Book_ID, 'All Books') end as Book_ID 
, NumOrders 
, coalesce(TotalSales, 'No Sales') as TotalSales
     from ( select author_id as Author_ID 
            , book_id as Book_ID
            , count(Distinct order_id) AS NumOrders
            ,(Select sum(quantity * order_price) from a_bkorders.order_details) as TotalSales
         from a_bkorders.order_headers
         join a_bkorders.order_details using (order_id) 
         join a_bkinfo.book_authors using (book_id)  
        where author_sequence = 1        
         group by Author_ID, Book_ID, TotalSales with rollup) tbl;

Answer 1

更新2

1. 看起来您不需要在 GROUP BY 中包含 TotalSales。看看你的查询，它没有任何意义。只需将其从内部选择中删除即可。

2. 要包含尚未售出的书籍，您必须使用外部联接

话虽如此，您的查询可能看起来像

SELECT COALESCE(author_id, 'All Authors') author_id
     , COALESCE(book_id, IF(author_id IS NULL, 'All Books', 'Subtotal')) book_id
     , COALESCE(total_quantity, 'No books') total_quantity
     , COALESCE(total_sales, 'No Sales') total_sales   
 FROM 
(    
 SELECT author_id 
      , b.book_id 
      , SUM(quantity) total_quantity  
      , SUM(quantity * order_price) total_sales   
   FROM book_authors b LEFT JOIN order_details d
     ON b.book_id = d.book_id
  WHERE author_sequence = 1           
  GROUP BY Author_id, Book_ID WITH ROLLUP  -- you don't need TotalSales here
) q;

示例输出：

+------------+------------+----------------+-------- --------+
| 作者 ID | 书号 | 总数量 | 总销售额 |
+------------+------------+----------------+-------- --------+
| 1 | 1 | 12 | 12 278.50 | 278.50
| 1 | 3 | 没有书 | 没有销售 |
| 1 | 小计 | 12 | 12 278.50 | 278.50
| 3 | 2 | 5 | 75.75 | 75.75
| 3 | 小计 | 5 | 75.75 | 75.75
| 所有作者 | 所有书籍 | 17 | 17 354.25 | 354.25
+------------+------------+----------------+-------- --------+

这是SQLFiddle演示