SQL查询 - 需要从不同的表中获取信息

Question

我想写一个查询来获得一个报告，显示哪本书已经被借出最多。我有一个查询来获取最实际的图书，但我需要能够显示该书的标题，该书位于另一个表中。

SELECT * FROM LOAN; 

LOANID  BOOKID  CUSTID OUTDATE INDATE DUEDATE 

SELECT * FROM BOOK; 

AUTHORID  BOOKID BKISBN BKSTATUS BKTITLE BKSERIES BKTYPE BKNUMBER 

下面的查询是我迄今为止，并得到BOOKID：

SELECT Q1.* FROM 
(SELECT BOOKID, COUNT(*) 
    AS BOOK_COUNT 
    FROM LOAN 
    GROUP BY LOAN.BOOKID) Q1, 
(SELECT MAX(Q2.BOOK_COUNT) 
    AS HIGH_COUNT 
    FROM (SELECT BOOKID, COUNT(*) 
    AS BOOK_COUNT 
    FROM LOAN 
    GROUP BY LOAN.BOOKID) Q2) Q3 
WHERE Q1.BOOK_COUNT = Q3.HIGH_COUNT; 

结果：

BOOKID BOOK_COUNT 
---------- ---------- 
     387   3 

现在我需要BkTitle从书籍表。

任何人都可以协助吗？

Answer 1

尝试

select b.bookid, b.BKTITLE , count(l.loanid) as cnt_loan 
from book b 
inner join loan l on l.bookid = b.bookid 
WHERE ROWNUM < 2 
group by b.bookid 
order by cnt_loan desc