Empty strings, or blanks, are handled differently, depending on the datatype.
Inserting an empty string ("") into a variable character type or text column inserts a single space. char columns are padded to the defined length.
All trailing spaces are removed from data that is inserted into varchar and univarchar columns, except in the case of a string that contains only spaces. Strings that contain only spaces are truncated to a single space. Strings that are longer than the specified length of a char, nchar, unichar, univarchar, varchar, or nvarchar column are silently truncated unless the string_rtruncation option is set to on.