Lets say I have two franchise of dance schools.

I have two tables. First table tells about students roll no. every

Table 1 =

```
Roll No.    Center ID   Name    Date
1   A   Anna    10/10/2020
1   A   Anna    11/10/2020
1   B   Anna    12/10/2020
2   A   Bella   12/10/2020
2   B   Bella   13/10/2020
3   A   Catty   10/10/2020

```

Table 2 =

```
Roll no.    Center ID   Report
1   A   Did well
1   A   Sick 
1   B   Needs more twist
2   A   Practice required
2   B   Did well
3   A   Needs more practice

```

Result table expected: I want in the result it should pick Center id as A only but Report should be from both the centers

```
Roll no.    Center ID   Report  Name
1   A   Did well ,Sick ,Needs more twist    Anna
2   A   Practice required,Did well  Bella
3   A   Needs more practice Catty

```

Could someone pls help.
['https://Stackoverflow.com/questions/69445978', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/11496279/']
By `dplyr`,

```
t1 %>%
  mutate(Report = t2$Report) %>%
  group_by(Roll_No.) %>%
  summarise(Center_ID = "A",
    Report = paste0(Report, collapse = ', '),
    Name = unique(Name)
    )

  Roll_No. Center_ID Report                           Name 
     <int> <chr>     <chr>                            <chr>
1        1 A         Did well, Sick, Needs more twist Anna 
2        2 A         Practice required, Did well      Bella
3        3 A         Needs more practice              Catty

```
```r
library(tidyverse)

a <- tribble(
  ~Roll, ~Center, ~Name, ~Date,
  1, "A", "Anna", "10/10/2020",
  1, "B", "Anna", "12/10/2020",
  3, "A", "Catty", "10/10/2020"
)

b <- tribble(
  ~Roll, ~Center, ~Report,
  1, "A", "Dis well",
  1, "A", "Sick",
  1, "B", "Needs more twist",
  3, "A", "Needs more practice"
)

a %>%
  left_join(b) %>%
  group_by(Roll, Center) %>%
  summarise(
    Report = c(Report, Name %>% unique()) %>% paste0(collapse = ",")
  )
#> Joining, by = c("Roll", "Center")
#> `summarise()` has grouped output by 'Roll'. You can override using the `.groups` argument.
#> # A tibble: 3 x 3
#> # Groups:   Roll [2]
#>    Roll Center Report                   
#>   <dbl> <chr>  <chr>                    
#> 1     1 A      Dis well,Sick,Anna       
#> 2     1 B      Needs more twist,Anna    
#> 3     3 A      Needs more practice,Catty

```

Created on 2021-10-05 by the [reprex package](https://reprex.tidyverse.org) (v2.0.0)