How to check SQL Tuning Advisor task is exist or not

Question

How to check SQL Tuning Advisor task is exist or not using DBMS_SQLTUNE,
I want to remove SQL Tuning Advisor task only if it is exist using DBMS_SQLTUNE.DROP_TUNING_TASK function

Answer 1

Two approaches.
1. Look up in DBA/USER_ADVISOR_TASKS, if it exists, drop it.
2. Drop it, ignore the exception
3. Drop it, catch the exception (specific exception if you want to rightly avoid such constructs as when others then null) obviously within an inner block is you want to catch and then move on to do other work.
SQL> declare
  2   e_no_such_task exception;
  3   pragma exception_init(e_no_such_task,-13605);
  4   procedure forgetaboutit
  5   as
  6   begin
  7      null;
  8   end;
  9  begin
10     begin
11       dbms_sqltune.drop_tuning_task('NON_EXISTENT_TASK');
12     exception
13          when e_no_such_task then
14               forgetaboutit;
15     end;
16     -- do something else
17     null;
18  end;
19  /
PL/SQL procedure successfully completed.
SQL> P.S. Ignore procedure forgetaboutit - just amusing myself...