Question

我需要一个查询，它将从书表中返回书籍列表

但它也会显示可用的书籍和书籍总数。

对于书籍数量，它将计算具有类似ISBN n数量的书籍数量，这将计算具有可用状态的类似ISBN的书籍数量

表格结构

Bookid booktitle author ISBN edition publisher price supplier volume language status

status contains available,issued

我希望结果为

BookTitle Author Publisher Location Total available

请解释该查询，因为我需要在许多表上实现它

我试过这个查询

select *,count(1) as Quantity from Book group  by Book.BookTitle

它成功地为我提供了总数

的图书清单

和

select *,count(1) as Quantity from Book where status='Available' group  by Book.BookTitle

它成功地为我提供了有多少可用的书籍。

但我需要总计和可用的组合..

Answer 1

您必须按SELECT查询中的所有项目进行分组。您可以计算（*）或总和（1）。我将这样做：

SELECT BookId, Name, Available, count(*) as Quantity
FROM Book GROUP BY Bookid,Name,Available

Answer 2

简介：

select isbn, booktitle, sum(case when status='available' then 1 else 0 end) as avail, count(*) as total
from Book
group by isbn, booktitle

http://sqlfiddle.com/#!2/80a41/5

我绝对建议你阅读第三范式

Answer 3

select d.* from (select BookTitle,Author,Publisher,Location,count(BookTitle) as Total, Status, Count(Status) as StatusQuantity from Book group by BookTitle,Author,Publisher,Location,Status)d where d.Status='Available'

Answer 4

试试这个：

SELECT 
     BookTitle,
     Author,
     Publisher,
     Location, 
     SUM(CASE WHEN status='available' THEN 1 ELSE 0 END) Available,
     COUNT(*) AS Total
FROM Book
GROUP BY BookTitle,Author,Publisher,Location

Answer 5

你有任何关键限制吗？
你必须拆分表..
使用 bookid或ISBN 作为主键，将状态存储在单独的表中。
这将很容易进一步处理，否则记录应该是多余的..

Sql查询可用书籍和总书籍数量

5 个答案: