spark case_when raw implementation

case_when_raw.r

dfletters <- data.frame(letter=letters) 
sparkletters <- sdf_copy_to(sc, dfletters, 'sometable', overwrite=T) 
    # or using sdf_register(name='sometable')
sparkletters

df2 <- sdf_sql(sc, "select letter as A1,
 CASE WHEN letter = 'b' OR letter='d' 
    THEN 'itsBorD'
    ELSE 
        CASE WHEN letter = 'c' 
            THEN 'itsC'
            ELSE 'Other'
        END
 END AS IS_B_COL 
 from sometable")
df2