In SQL Server, the FORMAT function is a powerful tool for formatting date and time values, as well as numeric values, into a specific format. It provides a flexible way to display the values in a manner that meets specific requirements or adheres to a particular locale.
Syntax
The general syntax of the FORMAT function is as follows:
FORMAT (value, format [, culture])
value: This is the expression to be formatted, such as a date, time, or numeric value.
format: This is the format pattern specifying how the value should be displayed.
culture: (Optional) This argument is used to specify the culture or locale for formatting. If not provided, the format is based on the default language setting of the server.
Examples
Here are a few examples to illustrate the use of the FORMAT function:
Formatting Dates
SELECT FORMAT(GETDATE(), 'yyyy-MM-dd') AS FormattedDate;
This query formats the current date as ‘YYYY-MM-DD’.
Formatting Times
SELECT FORMAT(GETDATE(), 'hh:mm:ss tt') AS FormattedTime;
This query formats the current time as ‘HH:MM:SS AM/PM’.
Formatting Numbers
SELECT FORMAT(1234567.89, 'N') AS FormattedNumber;
This query formats the numeric value as a number with commas and two decimal places.
Custom Formatting
SELECT FORMAT(GETDATE(), 'dddd, MMMM d, yyyy', 'en-US') AS CustomFormat;
This query formats the current date with a custom format and specifies the culture (in this case, ‘en-US’).
It’s important to note that the FORMAT function can have a performance impact, especially when used on large datasets. This is because it converts the date and time values to strings, and operations on strings can be more resource-intensive than working with native date and time types. If you’re dealing with a large number of records, consider the performance implications before using the FORMAT function extensively.
In addition to the standard date and time format patterns, you can create custom format patterns using various format specifiers. The Microsoft documentation provides a comprehensive list of format specifiers and examples that you can use to customize the output according to your requirements.