TO_DSINTERVAL converts a character string of CHAR, VARCHAR2, NCHAR, or NVARCHAR2 datatype to an INTERVAL DAY TO SECOND value.
char is the character string to be converted.
The only valid nlsparam you can specify in this function is NLS_NUMERIC_CHARACTERS. This argument can have the form:
NLS_NUMERIC_CHARACTERS = "dg"
where d and g represent the decimal character and group separator respectively. Neither character can be a space.
The following example selects from the employees table the employees who had worked for the company for at least 100 days on January 1, 1990:
SELECT employee_id, last_name FROM employees
WHERE hire_date + TO_DSINTERVAL('100 10:00:00')
<= DATE '1990-01-01';
EMPLOYEE_ID LAST_NAME
----------- ---------------
100 King
101 Kochhar
200 Whalen