title: replacing vales in one table with values from another table using multiple criteria
body: <p>I have two tables, one called accajd, which a screenshot of is shown below, which has the old and new values in it. and one called jobcost with about 15 fields, 3 of which need to be updated with the data from the accadj table (accno, jno, and saccno). What i need to do is everywhere in job cost that the data from the accno, jno, and saccno fields matches the accnoold, jnoold, and saccnoold from accadj, i need to replace the data in jobcost with the values from accnonew, jnonew, and saccnonew from accadj.</p>
  
  <p><img src="https://i.imgur.com/DeHuMUy.jpg" alt="accadj database sample"></p>
  
  <pre><code>update jobcost 
  set accno =(SELECT accadj.[accnonew] FROM accadj 
     WHERE accadj.id = jobcost.[jno] 
    AND accadj.[saccnoold] = jobcost.[saccno]),
  jno =(SELECT accadj.[accnonew] FROM accadj 
     WHERE accadj.id = jobcost.[jno] 
    AND accadj.[saccnoold] = jobcost.[saccno]),
  saccno =(SELECT accadj.[accnonew] FROM accadj 
     WHERE accadj.id = jobcost.[jno] 
    AND accadj.[saccnoold] = jobcost.[saccno])
  </code></pre>
  
  <p>this is all I could come up with as far as writing a query goes for this task, and its nowhere close to working. the jobcost table has about 15,000 entries, so this code would only end up replacing about 100 of them</p>