A、B、C张表,A表其中的两个字段分别为B的主键和C的主键,我想获取A表按某种条件筛选出来的10条数据,并且每一条数据都包含B的主键对应的B表中的那一行和C的主键对应的C表中的那一行。
需求场景:我想获取最新10篇文章,每一篇文章的字段都有作者ID,和栏目ID。但是只有ID不行啊,我在前台的文章列表中得显示每篇文章的作者的名字、性别、积分等等信息,还要显示栏目的标题等等信息。这个是用JOIN吧?我没学过这个JOIN,能帮我写一下么?
sql语句,求大神
sub.d_name,parent.d_name from dept sub left join dept parent on sub.t_id = parent.d_id where sub.d_id = 1003
sql语句编写,求大神帮忙
select Name, Score from (select *, dense_rank() over(order by Score desc) as N from Student) as tempwhere N <= 3结果就是成绩排名前3的所有学生有多少出多少 还有一种方法就是先获取前3的成绩,然后在学生里面找成绩符合其中一个的 select * from Student where Score in(select ...
有几个SQL语句求大神指点
1、insert into B(a) select a from A where a= '1'2、create view v_create_v select * from a create procedure p_ctrate_table as begin select * from A end3、(1)select count(*) from 职员表 group by 性别 (2)select case 分数 when >90 then '优' w...
求大神赐教SQL语句 so easy
楼主是否想把消息FromId和ToId换成用户的名字,如果是这样的话一下语句可以实现:select MessageId,MessageInfo,(select UserName from UserInfo where UserId=FromId) as FromUser,(select UserName from UserInfo where UserId=ToId) as ToUser,IsOpen,Date from Message ...
求助,一个sql语句不会写,跪求帮助啊
Union all Select name,-1*score From deleted ) S Group By name ) N on M.name=N.Name When matched Then update Set M.sumscore=M.sumscore+N.score When Not matched Then Insert Values(N.Name,N.score);End ...
求教大神,满足这样条件的sql语句应该怎么写?
insert into testTable ("星期一", "星期二")select sum("星期一"), sum("星期二")from (select 1 as "星期一", 2 as "星期二"from dual union all select 4 as "星期一", 5 as "星期二" from dual) t
sql 语句 求大神帮忙分析 “查询选修了所有课程的学生姓名”_百度知 ...
(1)select sname ftom student where not exist (2)(select * from course where not exist (3) (select * from sc where sno=student.sno and cno=course.cno))exist :表示当前字段值是否为空,括号内称为子查询——>得到的结果传给外查询(即括号外的查询)以上先进行查询(3),结果...
SQL求大师大神
select @salary=COUNT(1) from tb where Salary<3000 while (@salary*1.0)\/@total>0.5 begin update tb set Salary=case when Salary<1000 then Salary+300 when Salary between 1000 and 1999 then Salary+200 when Salary between 2000 and 2999 then Salary+100 else Salary+50 end print '...
sql语句计算满足1+2+…+n<8888的最大整数n.很急用,求大神相助谢谢...
DECLARE @n INT,@sum INT SET @sum = 0 SET @n = 1 SET @sum = @sum + @n WHILE(@sum < 8888)BEGIN SET @n = @n + 1 SET @sum = @sum + @n END PRINT(@n - 1)--此时的@n是最大整数n+1,因为1+2+...+n已经大于8888 ...
求大神指点以下SQL查询语句
1、这是sql中常用的“相关子查询”;2、相关子查询的执行依赖于外部查询。多数情况下是子查询的WHERE子句中引用了外部查询的表。 执行过程:(1)从外层查询中取出一个元组,将元组相关列的值传给内层查询。(2)执行内层查询,得到子查询操作的值。(3)外查询根据子查询返回的结果或结果集得到满足...