PostgreSQL 7.1.3 Documentation
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# 4.9. Network Address Type Functions

Table 4-18. `cidr` and `inet` Operators

Operator | Description | Usage
--- | --- | ---
< | Less than | inet '192.168.1.5' < inet '192.168.1.6'
<= | Less than or equal | inet '192.168.1.5' <= inet '192.168.1.5'
= | Equals | inet '192.168.1.5' = inet '192.168.1.5'
>= | Greater or equal | inet '192.168.1.5' >= inet '192.168.1.5'
> | Greater | inet '192.168.1.5' > inet '192.168.1.4'
<> | Not equal | inet '192.168.1.5' <> inet '192.168.1.4'
<< | is contained within | inet '192.168.1.5' << inet '192.168.1/24'
<<= | is contained within or equals | inet '192.168.1/24' <<= inet '192.168.1/24'
>> | contains | inet'192.168.1/24' >> inet '192.168.1.5'
>>= | contains or equals | inet '192.168.1/24' >>= inet '192.168.1/24'

All of the operators for `inet` can be applied to `cidr` values as well. The operators `<<`, `<<=`, `>>`, `>>=` test for subnet inclusion: they consider only the network parts of the two addresses, ignoring any host part, and determine whether one network part is identical to or a subnet of the other.

Table 4-19. `cidr` and `inet` Functions

Function | Returns | Description | Example | Result
--- | --- | --- | --- | ---
broadcast(inet) | inet | broadcast address for network | broadcast('192.168.1.5/24') | 192.168.1.255/24
host(inet) | text | extract IP address as text | host('192.168.1.5/24') | 192.168.1.5
masklen(inet) | integer | extract netmask length | masklen('192.168.1.5/24') | 24
netmask(inet) | inet | construct netmask for network | netmask('192.168.1.5/24') | 255.255.255.0
network(inet) | cidr | extract network part of address | network('192.168.1.5/24') | 192.168.1.0/24
text(inet) | text | extract IP address and masklen as text | text(inet '192.168.1.5') | 192.168.1.5/32
abbrev(inet) | text | extract abbreviated display as text | abbrev(cidr '10.1.0.0/16') | 10.1/16

All of the functions for `inet` can be applied to `cidr` values as well. The `host`(), `text`(), and `abbrev`() functions are primarily intended to offer alternative display formats.

Table 4-20. `macaddr` Functions

Function | Returns | Description | Example | Result
--- | --- | --- | --- | ---
trunc(macaddr) | macaddr | set last 3 bytes to zero | trunc(macaddr '12:34:56:78:90:ab') | 12:34:56:00:00:00

The function `trunc`(`macaddr`) returns a MAC address with the last 3 bytes set to 0. This can be used to associate the remaining prefix with a manufacturer. The directory `contrib/mac` in the source distribution contains some utilities to create and maintain such an association table.

The `macaddr` type also supports the standard relational operators (`>`, `<=`, etc.) for lexicographical ordering.

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