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| PostgreSQL 8.1.4 Documentation | ||||
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| Prev | Fast Backward | Chapter 9. Functions and Operators | Fast Forward | Next |
Table 9-31 shows the operators available for the cidr and inet types. The operators <<, <<=, >>, and >>= 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 9-31. cidr and inet Operators
| Operator | Description | Example |
|---|---|---|
| < | is less than | inet '192.168.1.5' < inet '192.168.1.6' |
| <= | is 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' |
| >= | is greater or equal | inet '192.168.1.5' >= inet '192.168.1.5' |
| > | is greater than | inet '192.168.1.5' > inet '192.168.1.4' |
| <> | is 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' |
Table 9-32 shows the functions
available for use with the cidr and inet
types. The host,
text, and abbrev
functions are primarily intended to offer alternative display
formats. You can cast a text value to inet using normal casting
syntax: inet(expression) or
colname::inet.
Table 9-32. cidr and inet Functions
| Function | Return Type | 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) | int | extract netmask length | masklen('192.168.1.5/24') | 24 |
set_masklen(inet, int) | inet | set netmask length for inet value | set_masklen('192.168.1.5/24', 16) | 192.168.1.5/16 |
netmask(inet) | inet | construct netmask for network | netmask('192.168.1.5/24') | 255.255.255.0 |
hostmask(inet) | inet | construct host mask for network | hostmask('192.168.23.20/30') | 0.0.0.3 |
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 netmask length as text | text(inet '192.168.1.5') | 192.168.1.5/32 |
abbrev(inet) | text | abbreviated display format as text | abbrev(cidr '10.1.0.0/16') | 10.1/16 |
family(inet) | int | extract family of address; 4 for IPv4, 6 for IPv6 | family('::1') | 6 |
Table 9-33 shows the functions
available for use with the macaddr type. The function
trunc(macaddr) returns a MAC
address with the last 3 bytes set to zero. 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.
Table 9-33. macaddr Functions
| Function | Return Type | 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 macaddr type also supports the standard relational operators (>, <=, etc.) for lexicographical ordering.