How many decimals do you need?

Do you user NUMBER or NUMBER(p,s) for your datatypes?

I posted last year about 1!=1

Today I realized this could be solved with the scale 🙂

SQL> drop table lsc_t
Table dropped.
SQL> create table lsc_t(x number, y number(*,6))
Table created.
SQL> insert into lsc_t values (1/3*3,1/3*3)
1 row created.
SQL> commit
Commit complete.
SQL> select * from lsc_t where x=1
no rows selected.
SQL> select * from lsc_t where y=1

X Y
---------- ----------
1.00000000 1

So if you have amounts in US$ or GB£ or CHF, do not use NUMBER, use NUMBER(*,6) or NUMBER(*,2) or whatever is relevant to your business!

2 thoughts on “How many decimals do you need?”

  1. Surachart Opun

    Thank You for good example
    perhaps

    !=

    SQL> select * from lsc_t where x=1/3*3;

    X Y
    ———- ———-
    1 1

    SQL> select * from lsc_t where y=1/3*3;

    no rows selected

    😉

  2. Sokrates

    Hallo Laurent,

    thank you for this useful posting

    SQL> select * from dual where 1/3*3=1;

    no rows selected

    SQL> select * from dual where cast(1/3*3 as number(*,6))=cast(1 as number(*,6));

    DUM
    ---
    X

    !

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