Error: Encountered a SELECT WHEN EXPECTING the following ( + - all mod num

Question

I have a conditional INSERT statement where I update the record if todays date is found in the table or i will INSERT a new record if that date is not found..
Insert statement that comes after ELSE works fine but IF part fails with the error
encountered a select when expecting the following
*( - + all case mod new null.. and lot more*
IF EXISTS
(SELECT (TO_CHAR(UpdateDate, 'MM/DD/YYYY')) FROM EmployeeUpdateEmails
     WHERE UpdateDate = select (TO_CHAR(sysdate, 'MM/DD/YYYY')) from dual)
     UPDATE EMPLOYEEUPDATEEMAILS
SET EMP_MGR_TOTAL_CHANGES = total
     WHERE UpdateDate = select (TO_CHAR(sysdate, 'MM/DD/YYYY')) from dual
ELSE
This is how EmployeeUpdateEmails table is created
CREATE TABLE EmployeeUpdateEmails
UpdateNum SMALLINT          PRIMARY KEY,
UpdateDate               DATE,
Emp_Mgr_Total_Changes SMALLINT,
Emp_Term_Total_Chnages SMALLINT
Please Help

Answer 1

IF EXISTS is not aproppriate syntax:
SQL> declare
  2  begin
  3   if exists (select count(*) from dual)
  4   then
  5     dbms_output.put_line('it exists');
  6   else
  7     dbms_output.put_line('it doesn''t exist');
  8   end if;
  9  end;
10  /
if exists (select count(*) from dual)
ERROR at line 3:
ORA-06550: line 3, column 5:
PLS-00204: function or pseudo-column 'EXISTS' may be used inside a SQL statement only
ORA-06550: line 3, column 2:
PL/SQL: Statement ignored
SQL> declare
  2   my_var number; 
  3  begin
  4  
  5   select count(*) into my_var
  6   from   dual;
  7  
  8   if my_var >= 1
  9   then
10     dbms_output.put_line('it exists');
11   else
12     dbms_output.put_line('it doesn''t exist');
13   end if;
14  end;
15  /
it exists
PL/SQL procedure successfully completed.If you're using SQL then
1) post the complete statement
2) mention your database version ( the result of: select * from v$version; )
3) consider using CASE:
SQL> select case
  2           when (select count(*) from dual) >= 1
  3           then 'it exists'
  4           else 'it doesn''t exist'
  5         end
  6  from   dual;
CASEWHEN(SELECTC
it exists
1 row selected.