Sqldf产生＆＃34; NULL＆＃34;使用delete语句

Question

首先，我使用select statment为使用此代码

年龄> gt = 100的人检索行

b <- sqldf('select * from newdata where age >=100')
Loading required package: tcltk
b
  age          job marital education default balance housing loan  contact day
1 150 entrepreneur  single  tertiary     yes    1136     yes   no cellular   3
2 130 entrepreneur  single  tertiary     yes    1136     yes   no cellular   3
  month duration campaign pdays previous poutcome   y
1   apr      345        2   249        7    other  no
2   apr      345        2   249        7    other yes

现在，当我使用delete statment删除这些行时，它给了我＆＃34; NULL＆＃34;当我检查数据时，我发现这些行仍然在那里尚未删除!!

s <- sqldf('delete from newdata where age >= 100')
s
NULL

请帮助。