Published 16 November 2017
CAST/CONVERT to var types without length
The length of VARCHAR, VARBINARY and NVARCHAR datatype in a CAST or CONVERT clause wasn’t explicitly specified.
When you convert a datatype to a varchar, you do not have to specify the length. If you don’t do so, SQL Server will use a Varchar length sufficient to hold the string. It is better to specify the length because SQL Server has no idea what length you may subsequently need.