mirror of https://github.com/postgres/postgres
Add information regarding date and time types and functions,
including arguments allowed.
This commit is contained in:
Thomas G. Lockhart
parent
54c38a95ee
commit
75ebaa748e
|
|
@ -1,6 +1,6 @@
|
|||
.\" This is -*-nroff-*-
|
||||
.\" XXX standard disclaimer belongs here....
|
||||
.\" $Header: /cvsroot/pgsql/src/man/Attic/built-in.3,v 1.7 1997/05/16 07:13:46 thomas Exp $
|
||||
.\" $Header: /cvsroot/pgsql/src/man/Attic/built-in.3,v 1.8 1997/07/02 14:13:14 thomas Exp $
|
||||
.TH BUILT-INS INTRO 04/01/97 PostgreSQL PostgreSQL
|
||||
.SH "DESCRIPTION"
|
||||
This section describes the data types, functions and operators
|
||||
|
|
@ -82,7 +82,11 @@ several possibilities for formats, such as date and time types.
|
|||
Some date and time types share code for data input. For those types (currently
|
||||
.IR datetime
|
||||
and
|
||||
.IR abstime )
|
||||
.IR abstime
|
||||
, and
|
||||
.IR timespan
|
||||
and
|
||||
.IR reltime )
|
||||
the input can have any of a wide variety of styles. For numeric date representations,
|
||||
European and US conventions can differ, and the proper interpretation is obtained
|
||||
by using the
|
||||
|
|
@ -129,22 +133,22 @@ offsets to GMT (e.g. "-08" or "-08:00" when in Pacific Standard Time).
|
|||
Dates are stored internally in Greenwich Mean Time. Input and output routines
|
||||
translate time to the local time zone of the server.
|
||||
.PP
|
||||
All special values allowed for
|
||||
.IR "absolute time"
|
||||
are also allowed for
|
||||
.IR "datetime".
|
||||
The special values \*(lqcurrent\*(rq,
|
||||
\*(lqinfinity\*(rq and \*(lq-infinity\*(rq are provided.
|
||||
\*(lqinfinity\*(rq specifies a time later than any valid time, and
|
||||
\*(lq-infinity\*(rq specifies a time earlier than any valid time.
|
||||
\*(lqcurrent\*(rq indicates that the current time should be
|
||||
The special values `current',
|
||||
`infinity' and `-infinity' are provided.
|
||||
`infinity' specifies a time later than any valid time, and
|
||||
`-infinity' specifies a time earlier than any valid time.
|
||||
`current' indicates that the current time should be
|
||||
substituted whenever this value appears in a computation.
|
||||
.PP
|
||||
The strings \*(lqnow\*(rq and \*(lqepoch\*(rq can be used to specify
|
||||
time values. \*(lqnow\*(rq means the current time, and differs from
|
||||
\*(lqcurrent\*(rq in that the current time is immediately substituted
|
||||
for it. \*(lqepoch\*(rq means Jan 1 00:00:00 1970 GMT.
|
||||
|
||||
The strings
|
||||
`now',
|
||||
`today',
|
||||
`yesterday',
|
||||
`tomorrow',
|
||||
and `epoch' can be used to specify
|
||||
time values. `now' means the current time, and differs from
|
||||
`current' in that the current time is immediately substituted
|
||||
for it. `epoch' means Jan 1 00:00:00 1970 GMT.
|
||||
|
||||
.SH "TIMESPAN"
|
||||
General-use time span is input using a wide range of
|
||||
|
|
@ -165,10 +169,10 @@ Time span is specified with the following syntax:
|
|||
@ Quantity Unit [Direction]
|
||||
.sp
|
||||
where
|
||||
Quantity is ..., '-1', '0', `1', `2', ...
|
||||
Quantity is ..., `-1', `0', `1', `2', ...
|
||||
Unit is `second', `minute', `hour', `day', `week', `month', `year',
|
||||
or abbreviations or plurals of these units.
|
||||
Direction is ``ago''
|
||||
Direction is `ago'.
|
||||
.fi
|
||||
.SH "ABSOLUTE TIME"
|
||||
Absolute time (abstime) is a limited-range (+/- 68 years) and limited-precision (1 sec)
|
||||
|
|
@ -196,17 +200,10 @@ Valid dates are from Dec 13 20:45:53 1901 GMT to Jan 19 03:14:04
|
|||
using Greenwich Mean Time; the input and output routines default to
|
||||
the local time zone.
|
||||
.PP
|
||||
The special absolute time values \*(lqcurrent\*(rq,
|
||||
\*(lqinfinity\*(rq and \*(lq-infinity\*(rq are also provided.
|
||||
\*(lqinfinity\*(rq specifies a time later than any valid time, and
|
||||
\*(lq-infinity\*(rq specifies a time earlier than any valid time.
|
||||
\*(lqcurrent\*(rq indicates that the current time should be
|
||||
substituted whenever this value appears in a computation.
|
||||
.PP
|
||||
The strings \*(lqnow\*(rq and \*(lqepoch\*(rq can be used to specify
|
||||
time values. \*(lqnow\*(rq means the current time, and differs from
|
||||
\*(lqcurrent\*(rq in that the current time is immediately substituted
|
||||
for it. \*(lqepoch\*(rq means Jan 1 00:00:00 1970 GMT.
|
||||
All special values allowed for
|
||||
.IR "datetime"
|
||||
are also allowed for
|
||||
.IR "absolute time".
|
||||
|
||||
.SH "RELATIVE TIME"
|
||||
Relative time (reltime) is a limited-range (+/- 68 years) and limited-precision (1 sec)
|
||||
|
|
@ -506,50 +503,62 @@ tinterval
|
|||
.SH "FUNCTIONS"
|
||||
Many data types have functions available for conversion to other related types.
|
||||
In addition, there are some type-specific functions.
|
||||
.PP
|
||||
For the
|
||||
date_part() and date_trunc()
|
||||
functions, arguments can be
|
||||
`year', `month', `day', `hour', `minute', and `second',
|
||||
as well as the more specialized quantities
|
||||
`decade', `century', `millenium', `millisecond', and `microsecond'.
|
||||
date_part() also allows
|
||||
`dow'
|
||||
to return day of week and `epoch' to return seconds since 1970.
|
||||
|
||||
.nf
|
||||
Functions:
|
||||
|
||||
abstime
|
||||
datetime datetime(abstime) convert to datetime
|
||||
bool isfinite(abstime) TRUE if this is a finite time
|
||||
datetime datetime(abstime) convert to datetime
|
||||
bool isfinite(abstime) TRUE if this is a finite time
|
||||
|
||||
date
|
||||
datetime datetime(date) convert to datetime
|
||||
datetime datetime(date,time) convert to datetime
|
||||
datetime datetime(date) convert to datetime
|
||||
datetime datetime(date,time) convert to datetime
|
||||
|
||||
datetime
|
||||
abstime abstime(datetime) convert to abstime
|
||||
float8 date_part(text,datetime) specified portion of date field
|
||||
bool isfinite(datetime) TRUE if this is a finite time
|
||||
abstime abstime(datetime) convert to abstime
|
||||
float8 date_part(text,datetime) specified portion of date field
|
||||
datetime date_trunc(text,datetime) truncate date at specified units
|
||||
bool isfinite(datetime) TRUE if this is a finite time
|
||||
|
||||
reltime
|
||||
timespan timespan(reltime) convert to timespan
|
||||
timespan timespan(reltime) convert to timespan
|
||||
|
||||
time
|
||||
datetime datetime(date,time) convert to datetime
|
||||
datetime datetime(date,time) convert to datetime
|
||||
|
||||
timespan
|
||||
float8 date_part(text,timespan) specified portion of time field
|
||||
bool isfinite(timespan) TRUE if this is a finite time
|
||||
reltime reltime(timespan) convert to reltime
|
||||
float8 date_part(text,timespan) specified portion of time field
|
||||
bool isfinite(timespan) TRUE if this is a finite time
|
||||
reltime reltime(timespan) convert to reltime
|
||||
|
||||
box
|
||||
box box(point,point) convert points to box
|
||||
float8 area(box) area of box
|
||||
box box(point,point) convert points to box
|
||||
float8 area(box) area of box
|
||||
|
||||
path
|
||||
bool isopen(path) TRUE if this is an open path
|
||||
bool isclosed(path) TRUE if this is a closed path
|
||||
bool isopen(path) TRUE if this is an open path
|
||||
bool isclosed(path) TRUE if this is a closed path
|
||||
|
||||
circle
|
||||
circle circle(point,float8) convert to circle
|
||||
polygon polygon(npts,circle) convert to polygon with npts points
|
||||
float8 center(circle) radius of circle
|
||||
float8 radius(circle) radius of circle
|
||||
float8 diameter(circle) diameter of circle
|
||||
float8 area(circle) area of circle
|
||||
circle circle(point,float8) convert to circle
|
||||
polygon polygon(npts,circle) convert to polygon with npts points
|
||||
float8 center(circle) radius of circle
|
||||
float8 radius(circle) radius of circle
|
||||
float8 diameter(circle) diameter of circle
|
||||
float8 area(circle) area of circle
|
||||
.fi
|
||||
|
||||
.SH "BINARY OPERATORS"
|
||||
This list was generated from the Postgres system catalogs with the
|
||||
query:
|
||||
|
|
|
|||
Loading…
Reference in New Issue