Syntax

ym_iso_format::=

Purpose

TO_YMINTERVAL converts its argument to a value of INTERVAL MONTH TO YEAR data type.

For the argument, you can specify any expression that evaluates to a character string of CHAR, VARCHAR2, NCHAR, or NVARCHAR2 data type.

TO_YMINTERVAL accepts argument in one of the two formats:

• SQL interval format compatible with the SQL standard (ISO/IEC 9075)

• ISO duration format compatible with the ISO 8601:2004 standard

In the SQL format, years is an integer between 0 and 999999999, and months is an integer between 0 and 11. Additional blanks are allowed between format elements.

In the ISO format, years and months are integers between 0 and 999999999. Days, hours, minutes, seconds, and frac_secs are non-negative integers, and are ignored, if specified. No blanks are allowed in the value. If you specify T, then you must specify at least one of the hours, minutes, or seconds values.

The optional DEFAULT return_value ON CONVERSION ERROR clause allows you to specify the value this function returns if an error occurs while converting the argument to an INTERVAL MONTH TO YEAR type. This clause has no effect if an error occurs while evaluating the argument. The return_value can be an expression or a bind variable, and it must evaluate to a character string of CHAR, VARCHAR2, NCHAR, or NVARCHAR2 data type. It can be in either the SQL format or ISO format, and need not be in the same format as the function argument. If return_value cannot be converted to an INTERVAL MONTH TO YEAR type, then the function returns an error.

Examples

The following example calculates for each employee in the sample hr.employees table a date one year two months after the hire date:

SELECT hire_date, hire_date + TO_YMINTERVAL('01-02') "14 months"
   FROM employees;

HIRE_DATE 14 months
--------- ---------
17-JUN-03 17-AUG-04
21-SEP-05 21-NOV-06
13-JAN-01 13-MAR-02
20-MAY-08 20-JUL-09
21-MAY-07 21-JUL-08

. . .

The following example makes the same calculation using the ISO format:

SELECT hire_date, hire_date + TO_YMINTERVAL('P1Y2M') FROM employees;

The following example returns the default value because the specified expression cannot be converted to an INTERVAL MONTH TO YEAR value:

SELECT TO_YMINTERVAL('1x-02'
       DEFAULT '00-00' ON CONVERSION ERROR) "Value"
  FROM DUAL;

Value
-------------
+000000000-00