What do the interval values in PostgreSQL mean?
Internally, PostgreSQL stores interval values as months, days, and seconds. The months and days values are integers while the seconds can field can have fractions. The interval values are very useful when doing date or time arithmetic. For example, if you want to know the time…
How to determine if two date ranges overlap?
The short (ish) answer is: given two date intervals A and B with components .start and .end and the constraint .start <= .end, then two intervals overlap if: A.end >= B.start AND A.start <= B.end You can tune the use of >= vs > and <= vs < to meet your requirements for degree of overlap.
What is the function date trunc in PostgreSQL?
The function date_trunc is conceptually similar to the trunc function for numbers. source is a value expression of type timestamp or interval. (Values of type date and time are cast automatically to timestamp or interval, respectively.) field selects to which precision to truncate the input value.
How to calculate time zone offset in PostgreSQL?
The minutes field (0 – 59) For timestamp values, the number of the month within the year (1 – 12) ; for interval values the number of months, modulo 12 (0 – 11) The time zone offset from UTC, measured in seconds. Positive values correspond to time zones east of UTC, negative values to zones west of UTC.
What does the precision p mean in PostgreSQL?
The precision p is the number of fraction digits retained in the second field. The at sign ( @) is optional therefore you can omit it. The following examples show some interval values: Internally, PostgreSQL stores interval values as months, days, and seconds. The months and days values are integers while the seconds can field can have fractions.
What is the function justifyhours in PostgreSQL?
PostgreSQL provides two functions justifydays and justifyhours that allows you to adjust the interval of 30-day as one month and the interval of 24-hour as one day: In addition, the justify_interval function adjusts interval using justifydays and justifyhours with additional sign adjustments:
How to write ISO 8601 time intervals in PostgreSQL?
In addition to the verbose syntax above, PostgreSQL allows you to write the interval values using ISO 8601 time intervals in two ways: format with designators and alternative format. The ISO 8601 format with designators is like this: P quantity unit [ quantity unit …]