title: How to add the sum of the 'sum of the two tables?'
body: <p>I created Tables T1 and T2. I managed to add their sum, but I can't seem to add the sum of the T1 and T2 together (10+12 = <strong>22</strong>)  by adding a sum() in the beginning of the code.</p>
  
  <pre><code>    CREATE TABLE T1(kW int)
      CREATE TABLE T2(kW int) 
  
      SELECT T1C1, T2C1
      FROM
       ( select SUM(Kw) T1C1 FROM  T1 ) A
      CROSS JOIN 
       ( select SUM(Kw) T2C1 FROM  T2 ) B
  
      BEGIN
      INSERT INTO T1 VALUES ('4');
      INSERT INTO T1 VALUES ('1');
      INSERT INTO T1 VALUES ('5');
      INSERT INTO T2 VALUES ('7');
      INSERT INTO T2 VALUES ('2');
      INSERT INTO T2 VALUES ('3');
      END
  </code></pre>