In PostgreSQL, the pg_typeof() function allows you to get the data type of any value.
More specifically, it returns the OID of the data type of the value that is passed to it. It returns a regtype, which is an OID alias type. Therefore it’s the same as an OID for comparison purposes but displays as a type name.
In PostgreSQL, clock_timestamp() is a non-SQL-standard time function that returns the current date and time.
An important consideration of this function is that its result changes throughout the execution of a statement. Therefore, you could get a different result in different parts of the statement if you call the function multiple times within a single statement.
Continue readingIn PostgreSQL, you can use the pg_sleep() function to delay execution for a given number of seconds.
It makes the current session’s process sleep until the specified number of seconds have elapsed. It works similar to MySQL‘s sleep() function, and also TSQL‘s waitfor statement in SQL Server.
The pg_sleep() function accepts a double precision argument, so you can also specify fractional-second delays.
The sleep delay will be at least as long as specified. However, it could be longer depending on factors such as server load, as well as your platform’s effective resolution of the sleep interval.
Continue readingIn PostgreSQL, you can use the pg_sleep_for() function to delay execution for a given interval.
It makes the current session’s process sleep until the specified interval has elapsed.
The sleep delay will be at least as long as specified. However, it could be longer depending on factors such as server load, as well as your platform’s effective resolution of the sleep interval.
Continue readingIn PostgreSQL, you can use the pg_sleep_until() function to delay execution until a specified timestamp.
This is useful for when a specific wake-up time is desired.
Note that pg_sleep_until is not guaranteed to wake up exactly at the specified time, but it will not wake up any earlier.
In Postgres, the age() function returns the age based on two timestamp or date variables.
The result is returned using years and months, rather than just days.
For example, a result might look like this: 3 years 2 mons 30 days.
Continue readingIn PostgreSQL, you can get the day name from a date by using the to_char() function. This function returns a string based on the timestamp and the template pattern you provide as arguments..
In PostgreSQL you can use the extract() function to get the year from a date.
You can also use the date_part() function to do the same thing.
SQLite supports five functions for working with dates and times. These are:
All of these functions accept a time string as an argument. They also accept other arguments for modifying/formatting the output.
The strftime() function is the most versatile function of the five. In fact, this function can do everything the other four can.
In other words, you could use strftime() for all your date and time formatting requirements. The other four functions are available solely for convenience.
The SQLite strftime() function enables you to return a date and time value in a specified format.
The actual date/time value returned is based on a time string that you provide as an argument when you call the function, as well as any modifiers you include (as optional arguments). A modifier allows you to change the date, such as add a number of days, set it to local time, etc
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