How to round a number including least significant zeros? - sql

Question

I am trying to execute following SQL query in Oracle
Select round ( 123.50000065 , 4 ) from dual;
Output : 123.5
Required output: 123.5000
Any help is appreciated. ..

Answer 1

You probably want to use to_char with required format:
Below rounds the value to 4 decimal places and formats into the required string:
Select to_char(123.50000065, '999999999990D9999') x from dual;
If you don't want to actually round the number i.e. you just want to truncate after 4 digits, use:
Select to_char(trunc(123.50000065, 4), '999999999990D9999') x from dual;

Answer 2

ROUND ( numeric_expression , length [ ,function ] )
SELECT ROUND(123.9994, 3), ROUND(123.9995, 3);
Output:
123.9990 124.0000

Answer 3

Instead of round(), use to_char() or cast() to a decimal type:
select to_char(val, '999.9999'),
cast(val as decimal(10, 4))

Answer 4

To control the format a number is showed, you can cast it to a string, by applying the right format mask.
Depending on how you need round your input value, one of these could be useful:
with test(x) as (
select 123.50000065 from dual union all
select 123.00004 from dual union all
select 123.00005 from dual union all
select 123.00008 from dual
)
select x,
to_char(x, 'FM99999999.0000'),
to_char(trunc(x, 4), 'FM99999999.0000')
from test ;
result:
X TO_CHAR(X,'FM9 TO_CHAR(TRUNC(
-------------------------- -------------- --------------
123,50000065000 123.5000 123.5000
123,00004000000 123.0000 123.0000
123,00005000000 123.0001 123.0000
123,00008000000 123.0001 123.0000

Answer 5

"Rounding" is a mathematical concept. The value (with your sample input) is 123.5. Mathematically 123.5000 is the same thing as 123.5. They are only different as STRINGS.
One way to display 123.5 as 123.5000 is to wrap round() within to_char(). However, this means you are not able to use it in further computations (actually Oracle will allow you to - it will do an implicit conversion back to number instead of throwing a data type mismatch error, as it should do).
The better way, in most cases, is to address formatting in your client software, like SQL Developer, SQL*Plus, or Toad. Here is how you can do it in SQL*Plus:
SQL> Select round ( 123.50000065 , 4 ) as result from dual;
RESULT
----------
123.5
-- change the format of the numeric column "result"
SQL> column result format 999.0000
SQL> Select round ( 123.50000065 , 4 ) as result from dual;
RESULT
---------
123.5000

Answer 6

I can't see how you got 123.5 from your query. mine results 123.50000000
if I understand correctly, you want your number 4 significant decimal places.
why not try cast
select cast(123.50000065 as numeric(38,4))
output: 123.5000
testing if it rounds off number:
select cast(123.50000065 as numeric(38,6))
output: 123.500001