我想计算有多少本书具有相同的名称，然后计算其中有多少书的状态 = 1

Question

我的代码：

SELECT ROW_NUMBER() OVER(ORDER BY Title ASC) as row, 
       Title, 
       BookNo, 
       COUNT(*) as Copies, 
       COUNT(Status = 1) 
from tbbook 
GROUP BY Title

result i got

Answer 1

查询不正确，您的 GROUP BY 表达式不完整。阅读 ONLY_FULL_GROUP_BY SQL 模式，您将修复查询。
COUNT(Status = 1) 显示 Status 不为 NULL 的行数。使用 SUM(Status = 1).

检查这个：

SELECT ROW_NUMBER() OVER(ORDER BY Title ASC) as RowNumber, 
       Title, 
       BookNo, 
       COUNT(*) AS CopiesAmount, 
       SUM(Status = 1) CopiesWithStatus_1
from tbbook 
GROUP BY Title, BookNo
ORDER BY Title ASC

https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=024afcc763715d6ffb52fee97156a797

Answer 2

我找到了答案及其子查询+内连接

我的代码：

SELECT ROW_NUMBER() OVER(ORDER BY Title ASC), tbbook.Title, COUNT(*), COALESCE(Available, 0) as Available
FROM tbbook 
LEFT JOIN (
    SELECT Title, COUNT(*) as Available
    from tbbook
    WHERE Status = 1
    GROUP by Title
    ) AS n on tbbook.Title = n.Title
GROUP BY Title

我想计算有多少本书具有相同的名称，然后计算其中有多少书的状态 = 1

I wanted to count how many books have same name then how many of those books have status = 1

mysql

count