What is the usage of the CAST function in SQL?

The CAST function in SQL is used to convert one data type to another data type.

The general syntax of the CAST function is as follows:

CAST(expression AS data_type)

In this case, the expression is the expression to be converted, and the data_type is the data type to be converted to.

For example, if you want to convert a string to an integer, you can use the CAST function as follows:

SELECT CAST('123' AS INT)

To convert an integer to a string, you can use the CAST function like this:

SELECT CAST(456 AS VARCHAR)

It is important to note that during the conversion process, incompatible types may arise. If the conversion cannot be carried out, the CAST function will throw an error. Therefore, when using the CAST function, it is necessary to ensure that the conversion is feasible.