title: Oracle Merge Into (Multiple Joined Tables) Update Set (Multiple Where Statements) Returns Invalid Column Specification
body: <p>I am new to Oracle. I am trying to update the values of a table with the values from a SELECT DISTINCT statement using the MERGE INTO method. I want to update the values for a table based on what is in the USING table conditionally.
  A quick diagram of what I am essentially going for is</p>
  
  <pre><code>MERGE
  INTO update_table ut
  USING 
  (SELECT DISTINCT
   t1.column_1
  ,t2.column_2
   FROM table_1 t1
   INNER JOIN table_2 t2
   ON t1.foreign_key = t2.primary_key) st
  ON (ut.pk = st.column_1)
  WHEN MATCH UPATE
  SET(ut.update_column = st.column_2 
      WHERE st.column_1 = 1 
      AND st.column_2 = 1
     ,ut.update_column = st.column_2 
      WHERE st.column_1 = 2 
      AND st.column_2 = 2);
  </code></pre>
  
  <p>However, when I do so I get the INVALID COLUMN SPECIFICATION error on the line where I use SET. How can I work around this to successfully update the table, preferably in ANSI standard?</p>