Question

I have a problem with the query I have a table newtable and have inserted values:

create table newtable(
col1 varchar2(3),
col2 varchar2(3),
col3 varchar2(3),
col4 varchar2(3),
col5 varchar2(3)
)

insert into newtable values(5,'m','q',4,3);

I want to add together the values in the columns which have only digits. In this case, I want the result to be 12 (5+4+3).

In Excel, I would do something similar with the countif function. How do I do this in Oracle?

Answer 1

You could create a function that either converts the string to a number or returns a 0 and use that function on each column

SQL> ed
Wrote file afiedt.buf

  1  create or replace function my_to_number( p_str in varchar2 )
  2    return number
  3  is
  4    l_num number;
  5  begin
  6    l_num := to_number( p_str );
  7    return l_num;
  8  exception
  9    when others then
 10      return 0;
 11* end;
SQL> /

Function created.

SQL> select my_to_number(col1) +
  2         my_to_number(col2) +
  3         my_to_number(col3) +
  4         my_to_number(col4) +
  5         my_to_number(col5)
  6    from newtable;

MY_TO_NUMBER(COL1)+MY_TO_NUMBER(COL2)+MY_TO_NUMBER(COL3)+MY_TO_NUMBER(COL4)+MY_T
--------------------------------------------------------------------------------
                                                                              12

In a relational database, however, it is almost certainly a mistake to design a data model where you are storing numeric data in a varchar2 column when you want to subsequently treat that data as a number to do things like add the numbers together. It is almost certainly a mistake to design a data model where a particular column will sometimes store a numeric value and sometimes store a string. So I would be exceptionally concerned that the design of newtable needs to be rethought.