'Convert implicit varchar max

When I use the CONVERT(VARCHAR(200), Field) to extract the first 200 characters of a varchar(max) field, SQL show me a warning on the select operator on the execution plan as in the below image

enter image description here This is the simple query I used:

select top ? convert(varchar(200),Column1) from Object1

I try to compare 3 select:

  1. the first one with convert enter image description here
  2. the second with the left function enter image description here
  3. the last without any trasformation. enter image description here

In terms of granted memory the result is the same and in the plan I can see that the compute scalar operator reduce the size of data after its execution. So, why the warning with convert?

sql-servertsqlsql-execution-plan


Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source

Related Questions