SQL String Function FORMAT()

In SQL, the FORMAT() function is used to format a value with a specified format. It is typically used to format numeric or date/time values, but can be used with other types of values as well.

Here is an example of using the FORMAT() function to format a numeric value with two decimal places:

SELECT FORMAT(1234.56789, 2) AS formatted_value;

In this example, the FORMAT() function is used to format the value 1234.56789 with two decimal places. The second argument of the function specifies the number of decimal places to display.

The FORMAT() function can also be used to format date/time values, as well as values in different number systems (such as binary, octal, or hexadecimal). The format specifier used in the function depends on the type of value being formatted.

It's important to note that the FORMAT() function is not supported by all database systems. In some systems, an equivalent function may be available with a different name or syntax.

Additionally, the FORMAT() function can have a performance impact on large datasets, since it involves converting the input value to a string and applying the specified format. As such, it should be used with caution and only when necessary. In some cases, it may be more efficient to format values in the application layer instead of in the database query.