SELECT au1.au_fname, au1.au_lname, au2.au_fname, au2.au_lname
FROM authors au1 INNER JOIN authors au2
ON au1.zip = au2.zip and au1.au_lname = au2.au_lname
WHERE au1.city = 'Oakland'
ORDER BY au1.au_fname ASC, au1.au_lname ASC
FROM authors au1 INNER JOIN authors au2
ON au1.zip = au2.zip and au1.au_lname = au2.au_lname
WHERE au1.city = 'Oakland'
ORDER BY au1.au_fname ASC, au1.au_lname ASC
那位打哥帮我说清楚 给你另外加50分 谢谢
表示两个表进行连接的条件.
inner join .. on ....
得到的记录应该是两表的交集,再去比较你的where条件
至于你为什么得到11条记录,建议楼主还是贴出表结构和数据出来看一下吧
FROM authors au1 INNER JOIN authors au2
ON au1.zip = au2.zip
慢慢體會
这是SQL自带的PUBS库