title: Oracle - "table is mutating, trigger/function may not see it" error on update a table with no trigger
body: <p>I am getting this error: "<strong>ORA-04091: table FASHIONRETAILER.Payslips is mutating, trigger/function may not see it</strong>" on when trying to update on Payslips table, which has no triggers in it. The screenshot is attached proving there is no trigger on the table. Below is my update statement:</p>
  
  <pre><code>UPDATE "Payslips" 
  SET "NETPAY" = calculate_net_pay(user_id)
  WHERE "PAYSLIPSID" = (
      SELECT "Payslips"."PAYSLIPSID" FROM "Payslips" 
      WHERE "Payslips"."USERID" = user_id AND "Payslips"."Date" = (
          SELECT MAX("Payslips"."Date") FROM "Payslips" WHERE "Payslips"."USERID" = user_id 
          AND "Payslips"."NETPAY" IS NULL));
  </code></pre>
  
  <p>The <code>calculate_net_pay(user_id)</code> function and the sub-query in WHERE constraint are working properly. </p>
  
  <p><a href="https://i.stack.imgur.com/T0Io6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/T0Io6.png" alt="No triggers on Payslips table"></a></p>