动态SQL语法及获取本周、本月、本年时间段值

if exists(select * from sysobjects where name=N'Week_GetTask' and type='P')
drop proc Week_GetTask
go
CREATE PROC Week_GetTask
@timeRange datetime,
@dep_id int,
@type varchar(10),
@finshable varchar(10)
AS
DECLARE @timeStart datetime,@timeEnd datetime,@sql varchar(500)

IF(@type='week')
--获取周时间段值
BEGIN
SELECT @timeStart = Dateadd(wk,datediff(wk,0,@timeRange),-1)
SELECT @timeEnd = Dateadd(wk,datediff(wk,0,@timeRange),6)
END
ELSE
IF(@type='month')
--获取月时间段值
BEGIN
SELECT @timeStart = Dateadd(mm,datediff(mm,0,@timeRange),0)
SELECT @timeEnd = Dateadd(ms,-3,dateadd(mm,datediff(m,0,@timeRange)+1,0))
END
ELSE
--获取年时间段值
BEGIN
SELECT @timeStart = Dateadd(yy,datediff(yy,0,@timeRange),0)
SELECT @timeEnd = Dateadd(ms,-3,Dateadd(yy,datediff(yy,0,@timeRange)+1,0))
END

SET @sql = 'select mes_id,title,multiPrincipalName'
SET @sql = @sql+' from [message] '
SET @sql = @sql+' where dep_id='
SET @sql = @sql+ cast(@dep_id as char(10))
SET @sql = @sql+' and '
SET @sql = @sql+''''+convert(varchar(10),@timeStart,120)+''''
SET @sql = @sql+'<=add_date and '
SET @sql = @sql+''''+convert(varchar(10),@timeEnd,120)+''''
SET @sql = @sql+'>= add_date'
SET @sql = @sql+' and towho<>'''' and multiPrincipalName<>'''' '

IF(@finshable='yes')
BEGIN
SET @sql = @sql + ' and finishRate=100'
END
ELSE
BEGIN
SET @sql = @sql + ' and finishRate<>100'
END

PRINT @sql
Exec(@sql)

GO

动态SQL基本语法文章，以下内容是转载
地址：http://tmsoft.lsxy.com/index.php?load=read&id=74

1 :普通SQL语句可以用Exec执行

Select * from tableName
Exec('select * from tableName')
Exec sp_executesql N'select * from tableName'

-- 请注意字符串前一定要加N

2:字段名，表名，数据库名之类作为变量时，必须用动态SQL

declare @fname varchar(20)
set @fname = 'FiledName'
Select @fname from tableName

-- 错误,不会提示错误，但结果为固定值FiledName,并非所要。
Exec('select ' + @fname + ' from tableName')
-- 请注意 加号前后的 单引号的边上加空格

当然将字符串改成变量的形式也可

declare @fname varchar(20)
set @fname = 'FiledName' --设置字段名

declare @s varchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句会报错</p>
<p>declare @s Nvarchar(1000) -- 注意此处改为nvarchar(1000)
set @s = 'select ' + @fname + ' from tableName'
Exec(@s) -- 成功
exec sp_executesql @s -- 此句正确

3. 输出参数

declare @num int,
@sqls nvarchar(4000)
set @sqls='select count(*) from tableName'
exec(@sqls)
--如何将exec执行结果放入变量中？

declare @num int,
@sqls nvarchar(4000)
set @sqls='select @a=count(*) from tableName '
exec sp_executesql @sqls,N'@a int output',@num output
select @num