Question

I’ve got a table that resembles this:

id
name
datetime
quantity

and I’d like to, with SQL, move these records from one table to another that will not have the quantity column, inserting record X times where X is the value of quantity so ….

id name       datetime    quantity
----------------------------------
5  book-order 15-Mar-2010 3

# becomes

id name       datetime  
------------------------
5  book-order 15-Mar-2010
6  book-order 15-Mar-2010
7  book-order 15-Mar-2010

Is there a way to do this in pure SQL?

Answer 1

Here is a way to do it, assuming that quantity is no more than 100:

insert into t2(name, datetime)
    select name, datetime
    from t1 join
         (select d1*10+d2 as num
          from (select 0 as n union all select 1 union all select 2 union all select 3 union all select 4 union all
                select 5 union all select 6 union all select 7 union all select 8 union all select 9
               ) d1 cross join
               (select 0 as n union all select 1 union all select 2 union all select 3 union all select 4 union all
                select 5 union all select 6 union all select 7 union all select 8 union all select 9
              ) d2
         ) nums
         on nums.num < t1.qty

The hard part is generating a numbers table, if the quantity gets too big.