Question

I’d like to get all the records from a huge table where any of the number columns countains a value greater than 0. What’s the best way to do it?

E.g.:

/* table structure*/
create table sometable (id number, 
                        somestring varchar2(12),
                        some_amount_1 number(17,3),
                        some_amount_2 number(17,3),
                        some_amount_3 number(17,3),
                        ...
                        some_amount_xxx number(17,3));
/* "xxx" > 100, and yeah I did not designed that table structure... */

And I want any row where any of the some_amount_n > 0 (even better solution is to add a field in the first place to show which field(s) are greater than zero).

I know I can write this with a huge some_amount_1 > 0 OR some_amount_2 > 0 OR ... block (and the field names with some case when but is there should be some more elegant solution, isn’t there?

Answer 1

Possible solutions:

1. Normalize the table. You said you are not allowed to. Try to convince those that forbid such a change by explaining the benefits (performance, ease of writing queries, etc).

2. Write the huge ugly OR query. You could also print it along with the version of the query for the normalized tables. Add performance tests (you are allowed to create another test table or database, I hope.)

3. Write a program (either in PL/SQL or in another procedural language) that produces the horrible OR query. (Again, print along with the elegant version)

4. Add a new column, say called Any_x_bigger_than_zero which is automatically filled with either 0 or 1 via a trigger (that uses a huge ugly OR). Then you just need to check: WHERE Test_x_bigger_than_zero = 1 to see if any of the rows is > 0

5. Similar to previous but even better, create a materialized view with such a column.