In what format is the date stored in the Date field?
The field date actually stores a string, but in a special format "Y-m-d". If the parameter date-time is active, then "Y-m-d H:i".
Y — full year.
m — month number with leading zero.
d — day number with leading zero.
H — hours.
i — minutes.
The display in the field for the user can be overridden using the field parameter output format in the date/time interface.
How do I convert a date by template, for example, from the current date to the date of the first of the month?
For example, let's use the dateFormat function. Check its documentation to see what the format letters are replaced with.
For example, let's get the first date of the month based on the current date:
=: dateFormat(date: $#nd; format: "Y-m-01")
How do I get the first day of the next month from the current date?
You need to get the first date of the month and the number of days in the month. Then add the number of days to the first date of the month:
= : dateAdd(date: $first_day; days: $days; format: "Y-m-d")
first_day: dateFormat(date: $#nd; format: "Y-m-01")
days: dateFormat(date: $#nd; format: "t")
How do I get the last day of the month by the current date?
The same as in the previous example, but one day needs to be subtracted from the number of days:
= : dateAdd(date: $first_day; days: $days; format: "Y-m-d")
first_day: dateFormat(date: $#nd; format: "Y-m-01")
days: dateFormat(date: $#nd; format: "t") - 1
How do I get the day of the week string?
The format parameter in date processing functions is responsible for this:
"D" – abbreviated version
"l" (lowercase L) — full name of the day of the week.
If the schema language is Russian, but the php locale on the server is English (90% of cases), you also need to specify the lang: "ru" parameter:
=: dateFormat(date: $#nd; format: "D"; lang: "ru")
What if it is in Russian?
Use the lang parameter with the value "ru" in date processing functions.
Does display setting of the date in the field effect the form in which it is stored?
No, displaying using date/time interface output format does not affect the storage form in any way.
Date comparison?
Dates are compared as strings. Therefore, "2021-12-20" will not be equal to "2021-21-20 16:30", but will be compared as greater or lesser.
For equal or not equal comparisons, convert the dates being compared to the same format — either Y-m-d or Y-m-d H:i.
If you had a date stored in Y-m-d, then when converting to Y-m-d H:i, the hours and minutes will be 00:00.