【发布时间】:2009-02-24 06:25:16
【问题描述】:
table name:id
col1:owner-name
col2:book-id1
col3:book-id2
table name:book-name
col1:id
col2:name
谁能给我一个查询以获得以下结果 owner-name,book1-name,book2-name 使用上面 2 个表
【问题讨论】:
table name:id
col1:owner-name
col2:book-id1
col3:book-id2
table name:book-name
col1:id
col2:name
谁能给我一个查询以获得以下结果 owner-name,book1-name,book2-name 使用上面 2 个表
【问题讨论】:
SELECT id.owner-name, b1.name "book1-name", b2.name "book2-name"
FROM id
LEFT JOIN book-name "b1" ON b1.id = id.book-id1
LEFT JOIN book-name "b2" ON b2.id = id.book-id2
【讨论】:
SELECT a.OWNER-NAME,b1.name book1,b2.name book2
FROM ID a,BOOK-NAME b1,BOOK-NAME b2
where a.book-id1= b1.id
and a.book-id2= b2.id
或
SELECT a.OWNER-NAME,
(SELECT b1.name from BOOK-NAME b1 where b1.id=a.book-id1) BOOK_NAME1,
(SELECT b2.name from BOOK-NAME b2 where b2.id=a.book-id2) BOOK_NAME2
FROM ID a
【讨论】: