解释一下下列SQL语句
select * from (SELECT ROWNUM as RECNO,TK_COMPANY.* FROM TK_COMPANY ORDER BY RECNO desC) WHERE RECNO
select count(COMPANY_ID) as total1 from TK_COMPANY
with OraQuerytotal do
begin
Close;
Sql.Clear;
Sql.Add('SELECT RowNum, RowId, T.* FROM Tk_Truck T where Length(COMPANY_ID)<5');
open;
While not eof do
begin
Edit;
for i:=0 to (COMPANY_ID_Length-length(FieldByName('COMPANY_ID').AsString)) do
COMPANY_ID:='0'+FieldByName('COMPANY_ID').AsString;
FieldByName('COMPANY_ID').AsString:=COMPANY_ID;
Post;
NExt;
end;
end;