Select DB2 Queries

Good morning,

By making a query in my DB2 Database, we noticed something curious. When I query a Table depending on the where condition, it displays the data.

SELECT NOMBRE    
  FROM X    
 WHERE NOMBRE = 'aaa '    

Result: "aaa_" - > "_" represents blank spaces

SELECT NOMBRE
  FROM X
 WHERE NOMBRE = 'aaa      '

Result: "aaa