Sql Syntax giving unknown syntax error - mysql

Question

I am having a problem with my mysql statement.
basically the code works perfectly when inserting, but as soon as the addnew variable=false and it switches to update it gives me an error that i cannot solve.
The Code:
procedure Tadddomain.BitBtn2Click(Sender: TObject);
Var
PrevSql:String;
ID:String;
begin
With Datalive.domains Do
Begin
id:=fieldbyname('id').AsString;
Active:=False;
prevsql:=sql.Text;
Sql.Clear;
Params.Clear;
Addparam(Datalive.domains,'client_id',ftinteger,datalive.clients.FieldByName('id').AsString);
Addparam(Datalive.domains,'domain_name',ftString,Edit1.Text);
Addparam(Datalive.domains,'register_date',ftdate,DateTimePicker1.Date);
Addparam(Datalive.domains,'registered_until',ftdate,DateTimePicker2.Date);
if addnew=true then
Sql.Text:='Insert into domains (client_id,domain_name,register_date,registered_until) VALUES (:client_id,:domain_name,:register_date,:registered_until)'
Else if addnew=False then
Sql.Text:='Update domains (domain_name=:domain_name, register_date=:register_date, registered_until=:registered_until) where id='''+id+'''';
Showmessage(sql.text);
execsql;
sleep(100);
sql.Text:=prevsql;
active:=True;
done:=True;
adddomain.Close;
End;
end;
The Error:
Project project1.exe raised exception class EZSQLException with message 'SQL Error: You have an error in your SQL syntax; check the manual that corresponds to your mysql server version for the right syntax to use near '(domain_name='asd',register_date='2014-11-09',registered_until='2015-11-09') w' at line 1'.
Any Assistance would be great, I have searched and searched and cannot find the fault.
Update:
I changed the edit code as suggested below, and now no errors apear what so ever. But also nothing happens. It does not edit the record.
if addnew=true then
Sql.Text:='Insert into domains (client_id,domain_name,register_date,registered_until) VALUES (:client_id,:domain_name,:register_date,:registered_until)'
Else if addnew=False then
Begin
sql.Add('Update domains');
sql.Add('set domain_name=:domain_name,');
sql.Add('register_date=:register_date,');
sql.Add('registered_until=:registered_until');
sql.Add('where id=:id');
End;

Answer 1

Update syntax is like this
Update domains
set domain_name = :domain_name,
register_date = :register_date,
registered_until = :registered_until
where id = :id

Answer 2

You declare the "client_id" parameter not the "id" parameter you use in the update statement.
where id = :id
should be
where id = :client_id

Answer 3

I have found the problem.
If i define the parameters before i use the sql.add() function the parameters are discarded.
When I moved the
Addparam(Datalive.domains,'client_id',ftinteger,datalive.clients.FieldByName('id').AsString);
Addparam(Datalive.domains,'domain_name',ftString,Edit1.Text);
Addparam(Datalive.domains,'register_date',ftdate,DateTimePicker1.Date);
Addparam(Datalive.domains,'registered_until',ftdate,DateTimePicker2.Date);
to just before the execsql; the problem was solved.