title: create table statement is slow
body: <p>I'm trying to create a new table using a sub-set of data from an existing table.</p>
  
  <p>Here is some sample data. This table has 7000 records:</p>
  
  <pre><code>create table numbersegment (startnum varchar(35),endnum varchar(35),id_prefix number(10));
  insert into numbersegment values('8175290000','8175299999','14108');
  insert into numbersegment values('8175300000','8175309999','14108');
  insert into numbersegment values('8175310000','8175319999','14108');
  insert into numbersegment values('8175320000','8175329999','14108');
  insert into numbersegment values('8175330000','8175339999','14108');
  </code></pre>
  
  <p>The User_info table has 35 million records:</p>
  
  <pre><code>create table user_info(num varchar(35),subid number(18),custid number(18)); 
  
  
  insert into user_info values('8175290031',100001234567891111,100001234567891111);
  insert into user_info values('8175290032',100001234567891112,100001234567891112);
  insert into user_info values('8175290033',100001234567891113,100001234567891113);
  insert into user_info values('8175290034',100001234567891114,100001234567891114);
  insert into user_info values('8175290035',100001234567891115,100001234567891115);
  </code></pre>
  
  <p>When I execute below SQL it takes around 20 minutes to create customer table</p>
  
  <pre><code> create table customer as 
   select 
     mk.num,
     nm.id_prefix||substr(mk.subid,6) new_sub_id,
     nm.id_prefix||substr(mk.custid,6) new_cust_id
   from user_info mk,
     numbersegment nm 
   where mk.num &gt;=nm.startnum 
   and mk.num    &lt;=nm.endnum;
  </code></pre>
  
  <p>Please suggest fastest way to create this table. </p>
  
  <p>Already tried few things  like parallel execution and Substr to match 1st character.</p>