Whenever you need to save datetime data, a question arises about what MySQL type to use. Do you go with a native MySQL DATE type or use an INT field to store date and time info as a plain number?In this article, I’ll explain MySQL’s native options and give you a comparison table of the most common datatypes. We’ll also benchmark some typical queries and reach some conclusions about which datatype to use in a given situation.
Beginning with SQL Server 2008, the datatypes which store date and time were greatly improved. Despite this, many legacy databases (and often newly developed ones) still useDatetimeandSmallDatetime, the original datatypes. Aside from the dwindling possibility of backwards compatibility issues, there is no advantage to using these old datatypes; as this article will show, the new implementations are superior in every way.SQL 2005 and Earlier: Datetime and SmallDatetimeDatetimeandSmallDatetimeare the original temporal SQL Server datatypes, and the only options available in SQL Server 2005 and earlier. During this time, SQL Server date support was widely criticized for its lack of options. Other database systems, such as Oracle, already featured individual datatypes for date and time, as well as specific functionality for time zones.
Anyone who had to schedule an intercontinental phone call knows that there is no such thing as a simpletimecallednow. What you should rather think about is a time comprised ofhere and now.The Earth rotates around its own axis. When it’ssolar noon(the sun is at its highest position) in one place, it’s already past noon in places to the east and it’s still before noon in places to the west.To make communication easier, at the end of the 19th century, the Earth was divided into 24 hour-wide
As a follow up to our article “The Most Useful Date and Time Functions in Oracle Database” , let’s review what date and time functions look like in MS SQL Server.Let’s start with functions that extract a year, month and day from a given date.SQL Server usesGETDATE()andSYSDATETIME()to get a current date and time. They are nondeterministic functions: views and expressions that reference these columns can’t be indexed. Both functions accept no arguments and return the local current date and time. The difference is, when we use
Date and time functions and formats are quite different in various databases. In this article, let’s review the most common functions that manipulates dates in an Oracle database.The functionSYSDATE()returns a 7 byte binary data element whose bytes represents:century,year,month,day,hour,minute,secondIt’s important to know thatselect sysdate from dualin SQL*Plus gives the same result asselect to_char(sysdate) from dualbecause SQL*Plus binds everything into character strings so it can print it. For more detailed explanation, look at
If your default programming language, like mine, is Java, you most likely wince at the very thought of date arithmetic. (It’s changed for the better with Java 8 but Vertabelo is not there yet.)The date arithmetic API in PostgreSQL is like abreath of fresh air.Interval ArithmeticYou can represent a time interval:Add an interval to a date or subtract an interval from a date:Truncating DatesYou can truncate dates to the specified precision.