我有三个表:页,附件,页附件SQL查询,计数为0计数
我有这样的数据:
page
ID NAME
1 first page
2 second page
3 third page
4 fourth page
attachment
ID NAME
1 foo.word
2 test.xsl
3 mm.ppt
page-attachment
ID PAGE-ID ATTACHMENT-ID
1 2 1
2 2 2
3 3 3
我想获得每页附件的数量也是当这个数字是0。我曾尝试用:
select page.name, count(page-attachment.id) as attachmentsnumber
from page
inner join page-attachment on page.id=page-id
group by page.id
我得到这样的输出:
NAME ATTACHMENTSNUMBER
second page 2
third page 1
我想获得这个输出:
NAME ATTACHMENTSNUMBER
first page 0
second page 2
third page 1
fourth page 0
如何得到0的一部分?
正如David B.提到这个查询不会运行。将组更改为'group by page.name' – edosoft 2009-01-21 13:04:07