V6_SUBNETN

Calculates a subnet address in CIDR (Classless Inter-Domain Routing) format from a varbinary or alphanumeric IPv6 address.

Behavior Type

Immutable

Syntax

V6_SUBNETN ( expression1, expression2 )

Parameters

expression1

(VARBINARY or VARCHAR) is the string to calculate.

Notes:

  • V6_SUBNETN(<VARBINARY>, <INTEGER>) returns VARBINARY.

    OR

  • V6_SUBNETN(<VARCHAR>, <INTEGER>) returns VARBINARY, after using V6_ATON to convert the <VARCHAR> string to <VARBINARY>.
 
expression2

(INTEGER) is the size of the subnet.

Notes

The following syntax masks a BINARY IPv6 address B so that the N left-most bits of S form a subnet address, while the remaining right-most bits are cleared.

V6_SUBNETN right-pads B to 16 bytes with zeros, if necessary and masks B, preserving its N-bit subnet prefix.

=> V6_SUBNETN(VARBINARY B, INT8 N) -> VARBINARY(16) S

If B is NULL or longer than 16 bytes, or if N is not between 0 and 128 inclusive, the result is NULL.

S = [B]/N in Classless Inter-Domain Routing notation (CIDR notation).

The following syntax masks an alphanumeric IPv6 address A so that the N leftmost bits form a subnet address, while the remaining rightmost bits are cleared.

=> V6_SUBNETN(VARCHAR A, INT8 N) -> V6_SUBNETN(V6_ATON(A), N) -> VARBINARY(16) S

Example

This example returns VARBINARY, after using V6_ATON to convert the VARCHAR string to VARBINARY: 

=> SELECT V6_SUBNETN(V6_ATON('2001:db8::8:800:200c:417a'), 28);
                           v6_subnetn                           
---------------------------------------------------------------
  \001\015\260\000\000\000\000\000\000\000\000\000\000\000\000

See Also