sql语句的多种写法
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Oracle Union All Query 根据指定ID，返回包含该ID的所有父级记录 一个DETAIL 表， item ,empid, money 1 001 100 2 001 150 ... ... ...
一个 TOTAL 表， empid , money 目的是想把DETAIL 表的每个empid 的数据汇总插入到TOTAL 表中， 写的语句是这样地， 写法1： update total a set money=(select sum(nvl(money,0)) from detail where a.empid= empid group by empid )
写法2：（有些不通用） drop table total; create table total as select empid,sum(nvl(money,0)) money from detail group by empid; 写法3： update total a set money=(select sum(nvl(money,0)) from detail where a.empid= empid ) 写法4： update total a set money=(select sum(nvl(b.money,0)) from detail b where a.empid=b.empid ) where exists (select 1 from detail b where a.empid=b.empid );
Q]如何使用Hint提示 [A] 在select/delete/update后写/*+ hint */ 如 select /*+ index(TABLE_NAME INDEX_NAME) */ col1... 注意/*和+之间不能有空格 如用hint指定使用某个索引
select /*+ index(cbotab) */ col1 from cbotab; select /*+ index(cbotab cbotab1) */ col1 from cbotab; select /*+ index(a cbotab1) */ col1 from cbotab a; 其中 TABLE_NAME是必须要写的，且如果在查询中使用了表的别名，在hint也要用表的别名来代替表名; INDEX_NAME可以不必写，Oracle会根据统计值选一个索引; 如果索引名或表名写错了，那这个hint就会被忽略;
CREATE PROCEDURE dbo.PostGetPostByPage ( @page int, @forumid int, @topornot int ) AS /* SET NOCOUNT ON */ declare @begin int,@end int,@f int,@l int,@count int,@top int select @top=count(*) from Posts as p1 where p1.PostID=(select min(PostID) from Posts as p2 where p1.ThreadID=p2.ThreadID) and p1.ForumID=@forumid and PostType=4 if @topornot=1 select p1.PostType,p1.Title,p1.UserName,p1.TotalViews,p1.PostID,p1.ThreadID,p1.ForumID,FileName, Reply=(select Count(*) from Posts as p2 where p1.ThreadID=p2.ThreadID)-1, LastDate=(select Max(PostDate)from Posts as p2 where p1.ThreadID=p2.ThreadID), LastWriter=(select UserName from posts as p2 where p2.PostID=(select Max(PostID)from Posts as p2 where p1.ThreadID=p2.ThreadID)) from Posts as p1 where p1.PostID=(select min(PostID) from Posts as p2 where p1.ThreadID=p2.ThreadID) and p1.ForumID=@forumid and PostType=4 else if @topornot=2 begin select @count=count(*) from Posts as p1 where p1.PostID=(select min(PostID) from Posts as p2 where p1.ThreadID=p2.ThreadID) and p1.ForumID=@forumid and PostType<>4 declare my_cursor SCROLL CURSOR for select p1.PostID from Posts as p1 where p1.PostID=(select min(PostID) from Posts as p2 where p1.ThreadID=p2.ThreadID) and p1.ForumID=@forumid and PostType<>4 order by (select max(PostID) from Posts as p2 where p1.ThreadID=p2.ThreadID) desc open my_cursor if @count+@top<25 and @page=1 begin select @f=1 select @l=@count end if @count+@top>=25 and @page=1 begin select @f=1 select @l=25-@top end if(@page*25-@top>@count) and @page>1 begin select @f=(@page-1)*25+1-@top select @l=@count end if(@page*25-@top<=@count) and @page>1 begin select @f=(@page-1)*25+1-@top select @l=@page*25-@top end fetch absolute @f from my_cursor into @begin fetch absolute @l from my_cursor into @end set nocount off select p1.PostType,p1.Title,p1.UserName,p1.TotalViews,p1.PostID,p1.ThreadID,p1.ForumID,FileName, Reply=(select Count(*) from Posts as p2 where p1.ThreadID=p2.ThreadID)-1, LastDate=(select Max(PostDate)from Posts as p2 where p1.ThreadID=p2.ThreadID), LastWriter=(select UserName from posts as p2 where p2.PostID=(select Max(PostID)from Posts as p2 where p1.ThreadID=p2.ThreadID)) from Posts as p1 where p1.PostID=(select min(PostID) from Posts as p2 where p1.ThreadID=p2.ThreadID) and p1.ForumID=@forumid and PostID<=@begin and PostID>=@end and PostType<>4 order by (select max(PostID) from Posts as p2 where p1.ThreadID=p2.ThreadID) desc close my_cursor end RETURN @@Rowcount GO ---------- 以下为一数据内容: 字段: 员工卡号(nvarchar) 打卡日期(smalldatetime) 打卡时间(smalldatetime) 687623 2004-5-26 2004-5-26 7:29:00 687623 2004-5-26 2004-5-26 11:5:00 687623 2004-5-26 2004-5-26 13:31:00 687623 2004-5-26 2004-5-26 17:33:00 687244 2004-5-26 2004-5-26 7:35:00 687244 2004-5-26 2004-5-26 11:1:00 687244 2004-5-26 2004-5-26 13:28:00 687244 2004-5-26 2004-5-26 17:24:00 : : : : : : : : :需达到以下效果: 员工卡号 打卡日期 打卡明细时间 687623 2004-5-26 7:29 11:5 13:31 17:33 687244 2004-5-26 7:35 11:1 13:28 17:24 其中, 打卡明细时间由上表的打卡时间而来 --创建一个合并处理函数(生成打卡明细时间)create function f_time(@员工卡号 nvarchar(6),@打卡日期 smalldatetime)returns varchar(8000)asbegin declare @re varchar(8000) set @re='' select @re=@re+' '+convert(char(5),打卡时间,108) from 数据表 where 员工卡号=@员工卡号 and 打卡日期=@打卡日期 return(stuff(@re,1,1,''))endgo --调用函数实现查询select 员工卡号,打卡日期,打卡明细时间=dbo.f_time(员工卡号,打卡日期)from 数据表group by 员工卡号,打卡日期 |
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