title: in codeigniter how do i do a join with a where clause
body: <p>so i have two tables, and i want to get all the rows from table 1 that meet the where clause conditions, and then join them with table two based on the join conditions.  </p>
  
  <p>here are the sample tables:</p>
  
  <pre><code>table1:
  
  col1   col2  col3
  1      a     val1
  2      b     val2
  3      c     val3
  
  table2:
  
  col1   col3
  1      someval1
  2      someval2
  3      someval3
  </code></pre>
  
  <p>now i want to grab all the rows in table 1 where col1 = 2, and join those rows with rows from table2 where table2.col1 = table1.col1.  Does that make sense?</p>