In SQLite, we can use the TIME() function to subtract one or more minutes from a time value.
For datetime values, we can use the DATETIME() function.
dates
3 Ways to Get the First Day of the Month in MySQL
Here are three methods we can use to return the first day of a given month in MySQL.
This could be the first day of the current month, or the first day of the month based on a date that we specify.
Getting the first day of the month allows us to perform further calculations on the resulting date, like adding a certain number of days to the start of the month, etc.
Add Seconds to a Time Value in SQLite
In SQLite, we can use the TIME() function to add a given number of seconds to a time value.
If we’re dealing with datetime values, we can use the DATETIME() function.
Subtract Hours from a Time Value in PostgreSQL
In PostgreSQL, we can use the - operator to subtract one or more hours from a time value.
By “time” value, this could be an actual time value, a timestamp, or an interval. We can also subtract hours from a date value or a date and time combination.
2 Ways to Get the Number of Days in a Month in SQLite
Here are two options for returning the number of days in a given month in SQLite. This could be the number of days in the current month, or it could be based on a given date.
How to Convert a Unix Timestamp to a Date/Time Value in PostgreSQL
In PostgreSQL, we can use the to_timestamp() function to convert a Unix timestamp value to a date/time value.
The Unix timestamp (also known as Unix Epoch time, Unix time, or POSIX time) is the number of seconds that have elapsed since 00:00:00 Thursday, 1 January 1970, Coordinated Universal Time (UTC).
Subtract Weeks from a Date in PostgreSQL
We can use the - operator to subtract one or more weeks from a date in PostgreSQL.
Get the Last Day of the Month in PostgreSQL
We can use the following technique in PostgreSQL to return the last day of a given month.
This could be the last day of the current month, or the last day of the month based on a date that we specify.