SQL Server - Cast and Convert

With SQL Server, you can convert one type to another, for example an INT to VARCHAR using either the CAST or CONVERT function.

Here are both options in action:

Using CAST

1

SELECT CAST(123 AS VARCHAR(10)) AS ConvertedValue;

Using CONVERT

1

SELECT CONVERT(VARCHAR(10), 123) AS ConvertedValue;

Key points

Always specify the length for VARCHAR (e.g., VARCHAR(10)), otherwise SQL Server uses a default length of 30.

If you omit the length, it might cause truncation or unexpected results in some contexts.

Documentation

Reference: Microsoft Learn.

Credits: Image from Microsoft Server