数据库连接表的SQL语句-(xisiamk)

1、数据库连接表的SQL语句2009-08-07 11:27select a.bookname,b.categoryname from bk_bookname a,bk_category bwhere a.categoryid=b.id(一般用于mysql中,相當于inner join內連接)   SELECT     bk_bookname.bookname, bk_category.categorynameFROM         bk_bookname

2、inner JOIN             bk_category ON bk_bookname.categoryid = bk_category.id注意 right join 、left join 的區別表A：            表B：1 SELECT * FROM A JOIN B ON A.Id = B.Id    將顯示

3、9     條數據。              Inner join(等值连接)只返回两个表中联结字段相等的行2 SELECT * FROM A LEFT JOIN B ON A.Id = B.Id      將顯示 12 條數據。             

4、(left join(左联接) 返回包括左表中的所有记录和右表中联结字段相等的记                                    3 SELECT * FROM A RIGHT JOIN B ON A.Id = B.Id

5、0;  將顯示 10 條數據。       (right join(右联接) 返回包括右表中的所有记录和左表中联结字段相等的记录)    4. SELECT * FROM A,B WHERE A.Id = B.Id等同于內聯接5. 找出A表，在Age 18到20之間的記錄SELECT * FROM A    WHERE (Age BETWEEN 18 AND 20)(如果 test_expression 的值大于或等于 begin_expression 的值并且小于

6、或等于 end_expression 的值，则 BETWEEN 返回 TRUE。)6. 找出單科分數前二位同學的姓名   SELECT Name FROM A join(SELECT TOP (2) Id, MAX(Score) AS score FROM B GROUP BY Id ORDER BY score DESC) as AAon A.id=AA.id7. 寫一個存儲過程，要求輸入ID找出該ID對應的姓名和最高分數，返回name:score，如：張六：90alter proc sp_totalscoreid int,return nvarchar(100) out

7、putasbegin    declare name nvarchar(50)    declare score int    select top 1 name=,score=b.score    from a join b on a.id=b.id    where a.id =id    order by b.score desc    set return=name+':