In SQL Server, you can use the DATEADD() function to add a specified time period to a given date. You can also use it to subtract a specified time period.
You can also combine DATEADD() with other functions to format the date as required. For example, you could take ‘2020-10-03’, add 10 years, then return the (increased) year component.
This article contains examples to demonstrate.
Continue readingIn SQL Server, you can use the T-SQL DATEDIFF() function to return the difference between two dates/times. It works on any expression that can be resolved to a time, date, smalldatetime, datetime, datetime2, or datetimeoffset value.
This article provides examples of the DATEDIFF() function in SQL Server.
In SQL Server, you can use the DATEDIFF_BIG() function instead of the DATEDIFF() function if you expect the returned value to be really big. For example, if you’re trying to find out how many milliseconds are in a 1000 years, you’ll get an error.
That’s because DATEDIFF() returns an int data type, and the result is too big for that data type to handle. On the other hand, the DATEDIFF_BIG() function returns a signed bigint data type, which means you can use it to return much larger values. In other words, you can use with a much larger range of dates.
Other than that, there’s not really any difference between the two functions.
The article provides examples of using the DATEDIFF_BIG() function in SQL Server.
Transact-SQL includes a bunch of functions that help us work with dates and times. One of the more common tasks when working with dates is to extract the different parts of the date. For example, sometimes we only want the year, or the month. Other times we might want the day of the week. Either way, there are plenty of ways to do this in SQL Server.
In particular, the following functions allow you to return the day, month, and year from a date in SQL Server.
These functions are explained below.
When working with dates in SQL Server, sometimes you might find yourself reaching for the DATEPART() function, only to realise that what you really need is the DATENAME() function. Then there may be other situations where DATEPART() is actually preferable to DATENAME().
So what’s the difference between the DATEPART() and DATENAME() functions?
Let’s find out.
In SQL Server, the T-SQL DATENAME() function returns a character string that represents the specified datepart of the specified date. For example, you can pass in 2021-01-07 and have SQL Server return only the month portion (January).
The return type for DATENAME() is nvarchar.
Examples below.
In SQL Server, the T-SQL DATEPART() function returns an integer that represents the specified datepart of the specified date. For example, you can pass in 2021-01-07 and have SQL Server return only the year portion (2021).
You can also extract the time portion. For example, you can pass in 2018-06-02 08:24:14.3112042 and have SQL Server return only the hour portion (8).
Examples below.
Continue readingSometimes when working with SQL Server (or any other DBMS for that matter), you need to return the short name for a month. By this I mean the 3 letter abbreviation of a month. For example, you need “Dec” instead of “December”.
Here are four ways you can extract the shortened month name from a date in SQL Server.
This article provides a solution to a problem you may occasionally encounter while using the DATEDIFF() function in SQL Server.
If you encounter the following error:
The datediff function resulted in an overflow. The number of dateparts separating two date/time instances is too large. Try to use datediff with a less precise datepart.
It’s because the return value is too large. The DATEDIFF() function returns its result as an int data type. The reason you got this message is that the return value is too big for the int data type. Fortunately there’s an easy way to fix this.
When querying a SQL Server database, there may be times where you don’t want null values to be returned in your result set. And there may be times where you do want them returned. But there may also be times where you do want them returned, but as a different value.
That’s what the ISNULL() function is for.
ISNULL() is a T-SQL function that allows you to replace NULL with a specified value of your choice.