title: Update using self join
body: <p>I have a table structure as follows in oracle:</p>
  
  <pre><code>create table uet_tmp_course
  (
      "COURSE_ID" NUMBER(4,0) NOT NULL ENABLE, 
      "CODE" VARCHAR2(10 BYTE) NOT NULL ENABLE, 
      "TITLE" VARCHAR2(50 BYTE) NOT NULL ENABLE, 
      "CREDIT_HRS" NUMBER(4,2) NOT NULL ENABLE, 
      "LEVEL_ID" NUMBER(2,0),
    "STATUS" NUMBER(2,0),
    "COURSE_TYPE_ID" VARCHAR2(50 BYTE), 
    "EQUIVALENCE" VARCHAR2(10 BYTE),
    "LAB_CODE" VARCHAR2(10 BYTE),
  
       CONSTRAINT "PK_COURSE1" PRIMARY KEY ("COURSE_ID"),
  
       CONSTRAINT "UK_COURSE_CODE1" UNIQUE ("CODE")
  );
  </code></pre>
  
  <p>I want to update the column lab_code's value (i.e. the 8th column) with the course_id instead of code. For example, in the first row instead of 'SE-101L', I want to have '102' i.e. the course_id of 'SE-101L'. I have tried joins, but they result in errors like parenthesis missing or single row query returns more than one row. I would be glad if someone can help. 
  Thank you. </p>
  
  <p><a href="https://i.stack.imgur.com/UivXh.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UivXh.png" alt="enter image description here"></a></p>