Len function on Float in SQLServer gives wrong length

Question

I am using the below query in SQL Server.

declare @dt float
set @dt = 1079938.05
select @dt AS Val,Convert(nvarchar(20),@dt) AS NVal, len(@dt) AS Len
         


        

Answer 1

LEN() works on [N]VARCHAR(), thus you're running into an implicit conversion from FLOAT to VARCHAR

see this: https://social.msdn.microsoft.com/Forums/sqlserver/en-US/a4ea2bc1-6f2f-4992-8132-f824fe4ffce0/length-of-float-values-in-ms-sql-server-gives-wrong-result?forum=transactsql

That means that LEN converts the value to VARCHAR before it actually calculates its length. That's because the length you get coincides with the length of your NVarChar value 1.07994e+006.