日期时间的函数和运算。
| Operator |
Example |
Result |
| + |
date '2001-09-28' + integer '7' |
date '2001-10-05' |
| + |
date '2001-09-28' + interval '1 hour' |
timestamp '2001-09-28 01:00:00' |
| + |
date '2001-09-28' + time '03:00' |
timestamp '2001-09-28 03:00:00' |
| + |
interval '1 day' + interval '1 hour' |
interval '1 day 01:00:00' |
| + |
timestamp '2001-09-28 01:00' + interval '23 hours' |
timestamp '2001-09-29 00:00:00' |
| + |
time '01:00' + interval '3 hours' |
time '04:00:00' |
| - |
- interval '23 hours' |
interval '-23:00:00' |
| - |
date '2001-10-01' - date '2001-09-28' |
integer '3' (days) |
| - |
date '2001-10-01' - integer '7' |
date '2001-09-24' |
| - |
date '2001-09-28' - interval '1 hour' |
timestamp '2001-09-27 23:00:00' |
| - |
time '05:00' - time '03:00' |
interval '02:00:00' |
| - |
time '05:00' - interval '2 hours' |
time '03:00:00' |
| - |
timestamp '2001-09-28 23:00' - interval '23 hours' |
timestamp '2001-09-28 00:00:00' |
| - |
interval '1 day' - interval '1 hour' |
interval '1 day -01:00:00' |
| - |
timestamp '2001-09-29 03:00' - timestamp '2001-09-27 12:00' |
interval '1 day 15:00:00' |
| * |
900 * interval '1 second' |
interval '00:15:00' |
| * |
21 * interval '1 day' |
interval '21 days' |
| * |
double precision '3.5' * interval '1 hour' |
interval '03:30:00' |
| / |
interval '1 hour' / double precision '1.5' |
interval '00:40:00' |
| Function |
Return Type |
Description |
Example |
Result |
| age(timestamp, timestamp) |
interval |
计算年龄（时间长度） |
age(timestamp '2001-04-10', timestamp '1957-06-13') |
43 years 9 mons 27 days |
| age(timestamp) |
interval |
计算到当前时间的年龄（时间长度） |
age(timestamp '1957-06-13') |
43 years 8 mons 3 days |
| clock_timestamp() |
timestamp with time zone |
当前日期时间 |
||
| current_date |
date |
当前日期 |
||
| current_time |
time with time zone |
当前时间 |
||
| current_timestamp |
timestamp with time zone |
当前日期时间 |
||
| date_part(text, timestamp) |
double precision |
计算给定单位时间的时间间隔 |
date_part('hour', timestamp '2001-02-16 20:38:40') |
20 |
| date_part(text, interval) |
double precision |
计算给定单位时间的时间间隔 |
date_part('month', interval '2 years 3 months') |
3 |
| date_trunc(text, timestamp) |
timestamp |
按照时间戳截取时间 |
date_trunc('hour', timestamp '2001-02-16 20:38:40') |
2001-02-16 20:00:00 |
| date_trunc(text, interval) |
interval |
按照间隔截取时间 |
date_trunc('hour', interval '2 days 3 hours 40 minutes') |
2 days 03:00:00 |
| extract(field from timestamp) |
double precision |
取时间单位的值 |
extract(hour from timestamp '2001-02-16 20:38:40') |
20 |
| extract(field from interval) |
double precision |
取时间单位的值 |
extract(month from interval '2 years 3 months') |
3 |
| isfinite(date) |
boolean |
是否是有限的日期 |
isfinite(date '2001-02-16') |
true |
| isfinite(timestamp) |
boolean |
是否是有限的日期 |
isfinite(timestamp '2001-02-16 21:28:30') |
true |
| isfinite(interval) |
boolean |
是否是有限的时间间隔 |
isfinite(interval '4 hours') |
true |
| justify_days(interval) |
interval |
转换时间单位为天(给的时间如果小于天，转化为HH:mm:ss) |
justify_days(interval '800 days') |
2 years 2 mons 20 days |
| justify_hours(interval) |
interval |
转换时间单位为小时(给的时间如果小于小时，转化为HH:mm:ss) |
justify_hours(interval '27 hours') |
1 day 03:00:00 |
| justify_interval(interval) |
interval |
将时间间隔转为合适的时间 |
justify_interval(interval '1 mon -1 hour') |
29 days 23:00:00 |
| localtime |
time |
本地时间 |
||
| localtimestamp |
timestamp |
本地日期时间 |
||
| make_date(year int, month int, dayint) |
date |
转换时间 |
make_date(2013, 7, 15) |
2013-07-15 |
| make_interval(years int DEFAULT 0,months int DEFAULT 0, weeks intDEFAULT 0, days int DEFAULT 0, hoursint DEFAULT 0, mins int DEFAULT 0,secs double precision DEFAULT 0.0) |
interval |
转换时间间隔（years, months, days, hours） |
make_interval(days => 10) |
10 days |
| make_time(hour int, min int, secdouble precision) |
time |
输入单个数字，输出时间格式 |
make_time(8, 15, 23.5) |
08:15:23.5 |
| make_timestamp(year int, month int,day int, hour int, min int, secdouble precision) |
timestamp |
输入单个数字，输出日期时间格式 |
make_timestamp(2013, 7, 15, 8, 15, 23.5) |
2013-07-15 08:15:23.5 |
| make_timestamptz(year int, month int,day int, hour int, min int, secdouble precision, [ timezone text ]) |
timestamp with time zone |
输入单个数字，输出日期时间格式 |
make_timestamptz(2013, 7, 15, 8, 15, 23.5) |
2013-07-15 08:15:23.5+01 |
| now() |
timestamp with time zone |
当前时间 |
||
| statement_timestamp() |
timestamp with time zone |
当前日期时间 |
||
| timeofday() |
text |
当前时间 |
||
| transaction_timestamp() |
timestamp with time zone |
事务开始的时间 |
||
| to_timestamp(double precision) |
timestamp with time zone |
Unix时间戳转换为日期时间 |
to_timestamp(1284352323) |
2010-09-13 04:32:03+00 |