Question

我是SQL的新手，我尽最大努力编写代码，但它似乎对我不起作用，所以非常感谢帮助。

问题是我需要列出每个发布者发布的图书总数，然后使用发布商代码从最高和最低列出它们。

我已经走到了这一步;

SELECT COUNT (pub_code)
FROM Library_Books
GROUP BY pub_code
ORDER BY pub_code

无论如何都会感激任何帮助

Answer 1

SELECT kb_pub_code, COUNT (kb_pub_code)    
FROM Library_Books    
GROUP BY kb_pub_code    
ORDER BY 2

Answer 2

你非常接近：

SELECT kb_pub_code, COUNT(*) TotalBooks
FROM Library_Books
GROUP BY kb_pub_code
ORDER BY TotalBooks DESC

TotalBooks是count列的别名，它计算每个kb_pub_code的总行数

您可以在ORDER BY中引用列别名：ie。ORDER BY TotalBooks DESC

注意，如果可以在Library_Books表中重复书籍，您可能需要DISTINCT计数。类似的东西：

SELECT kb_pub_code, COUNT(DISTINCT title) TotalBooks
FROM Library_Books
GROUP BY kb_pub_code
ORDER BY TotalBooks DESC

Answer 3

SELECT kb_pub_code
,COUNT (*) as 'TotalBooks'
FROM Library_Books
GROUP BY kb_pub_code
ORDER BY TotalBooks desc

编辑：有了可能重复的附加信息，您可能希望使用CTE。

With DistinctList as(
Select Distinct kb_pub_code as 'PubCode'
,kb_title as 'Title' 
FROM Library_Books)

Select PubCode
,Count(*) as 'TotalBooks'
From DistinctList
Group by PubCode
ORDER BY TotalBooks desc

Answer 4

ORDER BY DESC将按降序排序。发布商代码应包含在结果集（SELECT）中，否则您将不知道哪个发布者是计数。

SELECT kb_pub_code, COUNT (kb_pub_code)    
FROM Library_Books    
GROUP BY kb_pub_code    
ORDER BY COUNT(kb_pub_code) DESC

SQL order by和list

4 个答案: