How to convert empty spaces into null values, using SQL Server?

Question

I have a table and the columns on this table contains empty spaces for some records. Now I need to move the data to another table and replace the empty spaces with a N

Answer 1

Did you try this?

UPDATE table 
SET col1 = NULL 
WHERE col1 = ''

As the commenters point out, you don't have to do ltrim() or rtrim(), and NULL columns will not match ''.