In PostgreSQL, you can use the AT TIME ZONE clause to convert a timestamp to another timezone.
How make_interval() Works in PostgreSQL
In PostgreSQL, the make_interval() function creates an interval from years, months, weeks, days, hours, minutes and seconds fields.
You provide the years, months, weeks, days, hours, minutes and/or seconds fields, and it will return an interval in the interval data type.
Continue readingHow make_timestamptz() Works in PostgreSQL
In PostgreSQL, the make_timestamptz() function allows you to create a timestamp with time zone from its year, month, day, hour, minute and seconds fields, as well as an optional timezone field.
How make_date() Works in PostgreSQL
In PostgreSQL, the make_date() function allows you to create a date from its separate year, month and day fields.
Each date part is provided as an integer, and the result is returned as a date.
Continue readingHow make_time() Works in PostgreSQL
In PostgreSQL, the make_time() function allows you to create a time from its hour, minute and seconds fields.
How make_timestamp() Works in PostgreSQL
In PostgreSQL, the make_timestamp() function allows you to create a timestamp from its year, month, day, hour, minute and seconds fields.
How statement_timestamp() Works in PostgreSQL
In PostgreSQL, the statement_timestamp() function returns the current date and time (including the time zone offset), at the start of the current statement.
The function doesn’t accept any parameters, so you can’t specify its precision.
Also, statement_timestamp() is a non-SQL-standard function.
How transaction_timestamp() Works in PostgreSQL
In PostgreSQL, the transaction_timestamp() function returns the current date and time (including the time zone offset), at the start of the current transaction.
It’s the equivalent of the traditional Postgres function now().
It’s also similar to the current_timestamp function (when called without an argument), except that it’s named to clearly reflect what it does.
The transaction_timestamp() function doesn’t accept any parameters, so you can’t specify its precision, whereas current_timestamp can be called with or without a precision parameter.
Also, transaction_timestamp() is a non-SQL-standard function.
How Now() Works in PostgreSQL
In PostgreSQL, the now() function returns the current date and time (including the time zone offset), at the start of the current transaction.
It’s the equivalent of the transaction_timestamp() function.
It’s also similar to the current_timestamp function (when called without an argument).
The now() function doesn’t accept any parameters, so you can’t specify its precision, whereas current_timestamp can be called with or without a precision parameter.
Also, now() is non-SQL-standard (as is the transaction_timestamp() function).
How timeofday() Works in PostgreSQL
In PostgreSQL, timeofday() is a non-SQL-standard time function that returns the current date and time, with the time zone abbreviation.
It’s similar to the clock_timestamp() function, except that it returns its result as a formatted text string rather than a timestamp with time zone value.
The result of both functions changes throughout the execution of a statement. Therefore, you could get a different result in different parts of the statement if you call the functions multiple times within a single statement.
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