Oracle 21c

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create table mytable (my_column) as
select '11,2' from dual union all
select '5,2' from dual union all
select '11,4' from dual union all
select '6,6' from dual union all
select '0,1' from dual
5 rows affected

select REGEXP_SUBSTR(my_column,'[^,]+',1,1) from myTable;

REGEXP_SUBSTR(MY_COLUMN,'[^,]+',1,1)

11

5

11

6

0

drop table mytable;
create table mytable (my_column) as
select 11.2 from dual union all
select 5.2 from dual union all
select 11.4 from dual union all
select 6.6 from dual union all
select 0.1 from dual
5 rows affected

alter session set nls_numeric_characters = ',.'
select my_column, to_char(my_column) from myTable;

MY_COLUMN
TO_CHAR(MY_COLUMN)

11,2
11,2

5,2
5,2

11,4
11,4

6,6
6,6

,1
,1

select REGEXP_SUBSTR(my_column,'[^,]+',1,1) from myTable;

REGEXP_SUBSTR(MY_COLUMN,'[^,]+',1,1)

11

5

11

6

1

select TRUNC(my_column) from myTable;

TRUNC(MY_COLUMN)

11

5

11

6

0