I have a question about merge function, there are three dataframe down below,

df1 <- data.frame("id"=c(1:6), "v1"=c(200, 300, 400, 500, 600, 200), 
                  "v2"=c(5, 6, 7, 8, 12, 44))

df2 <- data.frame("id"=c(2, 4, 7, 9), "v3"=c(2, 5, 8, 22))

df3 <- data.frame("id"=c(1, 3, 11, 22), "v3"=c(15, 17, 33, 22))

df1
id  v1 v2
1  1 200  5
2  2 300  6
3  3 400  7
4  4 500  8
5  5 600 12
6  6 200 44

df2
  id v3
1  2  2
2  4  5
3  7  8
4  9 22

df3
  id v3
1  1 15
2  3 17
3 11 33
4 22 22

What I want to do is left join by id by merge function, just like down below,

  id  v1 v2   v3
1  1 200  5   15   
2  2 300  6    2   
3  3 400  7   17   
4  4 500  8    5   
5  5 600 12   NA   
6  6 200 44   NA   

but my result is

df1 <- merge(df1, df2, by="id", all.x = T)
df1 <- merge(df1, df3, by="id", all.x = T)

df1
  id  v1 v2 v3.x v3.y
1  1 200  5   NA   15
2  2 300  6    2   NA
3  3 400  7   NA   17
4  4 500  8    5   NA
5  5 600 12   NA   NA
6  6 200 44   NA   NA

Can someone help me, I can’t find the relative question here, thank you!

>Solution :

Try with

merge(df1, rbind(df2, df3), by="id", all.x = T)