DECLARE @WHERES VARCHAR(1000)
DECLARE @a datetime
DECLARE @b datetime
DECLARE @c varchar(100)
set @a=N'2012-08-14 15:00:00'
set @b=N'2012-08-14 19:30:00'
set @c='CAA396ED-9DE2-4C80-B4A8-0BFBF3DBBC33'
SET @WHERES='AND CompanyId='+@c+' AND GpsTime>='+quotename(@a,'''')
+' AND GpsTime<='+QUOTENAME(@b,'''')
print @WHERES
--AND CompanyId=CAA396ED-9DE2-4C80-B4A8-0BFBF3DBBC33 AND GpsTime>='08 14 2012  3:00PM' AND GpsTime<='08 14 2012  7:30PM'
if @@ERROR<>0
begin
 SET @WHERES=''
end


--直接用quotename就行了

------解决方案--------------------

DATETIME需要转换，GUID需要引号

SQL code
DECLARE @WHERES VARCHAR(1000)
DECLARE @a datetime
DECLARE @b datetime
DECLARE @c varchar(100)
set @a=N'2012-08-14 15:00:00'
set @b=N'2012-08-14 19:30:00'
set @c='CAA396ED-9DE2-4C80-B4A8-0BFBF3DBBC33'
SET @WHERES='AND CompanyId='''+@c+''' AND GpsTime>='''+CONVERT(VARCHAR(19),@a,120)+''' AND GpsTime<='''+CONVERT(VARCHAR(19),@b,120)+''''

if @@ERROR<>0
begin
 SET @WHERES=''
end

------解决方案--------------------
SQL code
DECLARE @WHERES VARCHAR(1000)
DECLARE @a datetime
DECLARE @b datetime
DECLARE @c varchar(100)
set @a=N'2012-08-14 15:00:00'
set @b=N'2012-08-14 19:30:00'
set @c='CAA396ED-9DE2-4C80-B4A8-0BFBF3DBBC33'
SET @WHERES='AND CompanyId='''+@c+''' AND 
GpsTime>='''+CONVERT(VARCHAR(19),@a,120)+''' AND GpsTime<='''+CONVERT(VARCHAR(19),@b,120)+''''

if @@ERROR<>0
begin
 SET @WHERES=''
end