Insert into a Table from Another Table

See more:

SQL

SQL-Server

SQL-Server-2008

I've a two tables in SQL server 2008. One is tempTable(with 28 columns) which contains 1.7 million rows. It also has an identity column, named RowID . Other is BaseTable(with 52 columns). Now I've to insert all the rows from tempTable to BaseTable with modified value. I did like following ...

declare @i int
select @i=MAX(RowID) from tempTable
declare @a varchar(10), @b datetime, @c char(10), @d bit, @e int=0, ... and so on
while(@i<0)
BEGIN
select @a=Col1, @b=Col2, @c=Col3, @d=Col4, @e=Col5, ....so on ... from tempTable where RowId=@i
set @a += 'Hello'
set @b = datediff(...)
if(@e>10000) then
begin @d=1 end
set @e = cast(Col9 as int)*1.1
.
.
.
.
so on.......(thus I've to edit all the values)

insert into BaseTable(Col2, Col3, Col6, ......) values (@c, @a, @d, @b, @e, ........)
set @i -= 1
END

But it takes long time for insertion ...
Is there any other way to update tempTable & then insert into BaseTable effectively ???
Thanks in Advance...