How to compare strings in sql ignoring case?

If you are matching the full value of the field use

WHERE UPPER(fieldName) = 'ANGEL'

EDIT: From your comment you want to use:

SELECT 
    RPAD(a.name, 10,'=') "Nombre del Cliente"
    , RPAD(b.name, 12,'*') "Nombre del Consumidor" 
FROM 
    s_customer a, 
    s_region b 
WHERE 
    a.region_id = b.id 
    AND UPPER(a.name) LIKE '%SPORT%'