title: ORA-00905: Missing Keyword error on select statement
body: <p>I get an error in the below select query. This is the error I receive:</p>
  
  <blockquote>
    <p>ORA-00905: Missing Keyword</p>
  </blockquote>
  
  <p>Can anyone help ?</p>
  
  <pre><code>SELECT ni.node_installation_id,ni.customer_node_id,ni.customer_id,c.brand_name_1,substr(nitr.name,1,instr(nitr.name, ' ')-1) as node_inst_type
      from node_installation ni , customer c , node_inst_type_release nitr
      where ( Case 
              WHEN ni.arne_timestamp is null  THEN ( case  
                                                     when ni.arne_flag ='I' then ni.arne_flag ='I'
                                                     END )
       else (trunc(sysdate) - trunc(ni.arne_timestamp) &gt;= 60)
        end)     
  and ni.customer_id = c.customer_id 
  and ni.node_inst_type_release_id = nitr.node_inst_type_release_id
  and ni.no_of_collection_node_missed &gt;= 4
  and c.customer_id =90;
  </code></pre>