What is the CAST() Function?

The SQL server CAST() function allows you to explicitly convert data from one data type to another. Whether you need to change a string to a number, adjust the precision of a decimal, or alter the format of a date, the CAST() function provides the flexibility to manipulate your data to meet specific requirements. Understanding how to use this function effectively can streamline your data management processes and enhance the accuracy of your database queries. The syntax of the CAST() function is as follows:

CAST ( expression AS data_type [ ( length ) ] )

Here:

• expression represents the value to be converted.
• data_type denotes the target data type to which the expression will be converted.
• length (optional) specifies the length of the target data type, particularly relevant for character data types like VARCHAR. The default value is 30.

The CAST() function can convert values of any data type to one of the following data types: bigint, int, smallint, tinyint, bit, decimal, numeric, money, smallmoney, float, real, datetime, smalldatetime, char, varchar, text, nchar, nvarchar, ntext, binary, varbinary, or image.

In SQL Server, manipulating data is a fundamental aspect of database management. Often, you’ll find yourself needing to transform data from one type to another, either for calculations, comparisons, or presentation purposes. This is where the CAST() function comes. In this article, we will learn about the CAST() function in SQL Server, which is used to convert a value from one data type to another.