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1. Inner Join (3 points) Perform an inner join between the customers and orders datasets.

  q1<- inner_join(customers,orders)
## Joining with `by = join_by(customer_id)`

a. How many rows are in the result?
There are 4 rows

b. Why are some customers or orders not included in the result?
The customer date has only 3 customers in the order table where one customer has 2 orders

c. Display the result

 print(q1)
## # A tibble: 4 × 6
##   customer_id name    city        order_id product amount
##         <dbl> <chr>   <chr>          <dbl> <chr>    <dbl>
## 1           1 Alice   New York         101 Laptop    1200
## 2           2 Bob     Los Angeles      102 Phone      800
## 3           2 Bob     Los Angeles      104 Desktop   1500
## 4           3 Charlie Chicago          103 Tablet     300

2. Left Join (3 points) Perform a left join with customers as the left table and orders as the right table.

 q2<-left_join(customers,orders)
## Joining with `by = join_by(customer_id)`

a. How many rows are in the result?
There are 6 rows
b. Explain why this number differs from the inner join result.
Left_Join returns all rows from the left table and matching rows from the right table even even those without information for the right table
c. Display the result

 print(q2)
## # A tibble: 6 × 6
##   customer_id name    city        order_id product amount
##         <dbl> <chr>   <chr>          <dbl> <chr>    <dbl>
## 1           1 Alice   New York         101 Laptop    1200
## 2           2 Bob     Los Angeles      102 Phone      800
## 3           2 Bob     Los Angeles      104 Desktop   1500
## 4           3 Charlie Chicago          103 Tablet     300
## 5           4 David   Houston           NA <NA>        NA
## 6           5 Eve     Phoenix           NA <NA>        NA

3. Right Join (3 points) Perform a right join with customers as the left table and orders as the right table.

 q3<-right_join(customers,orders)
## Joining with `by = join_by(customer_id)`

a. How many rows are in the result?
There are 6rows
b. Which customer_ids in the result have NULL for customer name and city? Explain why.
Customer_ids 6 and 7 have no results for customer name and city because they have no data in customers table
c. Display the result

print(q3)
## # A tibble: 6 × 6
##   customer_id name    city        order_id product amount
##         <dbl> <chr>   <chr>          <dbl> <chr>    <dbl>
## 1           1 Alice   New York         101 Laptop    1200
## 2           2 Bob     Los Angeles      102 Phone      800
## 3           2 Bob     Los Angeles      104 Desktop   1500
## 4           3 Charlie Chicago          103 Tablet     300
## 5           6 <NA>    <NA>             105 Camera     600
## 6           7 <NA>    <NA>             106 Printer    150

4. Full Join (3 points) Perform a full join between customers and orders.

q4<-full_join(customers,orders)
## Joining with `by = join_by(customer_id)`

a. How many rows are in the result?
There are 8 rows
b. Identify any rows where there’s information from only one table. Explain these results.
Rows 5, 6, 7, and 8 all have data from one table.Full_Join includes all rows from both tables regardless of missing data
c. Display the result

print(q4)
## # A tibble: 8 × 6
##   customer_id name    city        order_id product amount
##         <dbl> <chr>   <chr>          <dbl> <chr>    <dbl>
## 1           1 Alice   New York         101 Laptop    1200
## 2           2 Bob     Los Angeles      102 Phone      800
## 3           2 Bob     Los Angeles      104 Desktop   1500
## 4           3 Charlie Chicago          103 Tablet     300
## 5           4 David   Houston           NA <NA>        NA
## 6           5 Eve     Phoenix           NA <NA>        NA
## 7           6 <NA>    <NA>             105 Camera     600
## 8           7 <NA>    <NA>             106 Printer    150

5. Semi Join (3 points) Perform a semi join with customers as the left table and orders as the right table.

q5<-semi_join(customers,orders)
## Joining with `by = join_by(customer_id)`

a. How many rows are in the result?
There are 3 rows
b. How does this result differ from the inner join result?
It differs from the Inner_Join result as there are no repeats in orders as orders are not included in the table but are used to match with the customer table
c. Display the result

print(q5)
## # A tibble: 3 × 3
##   customer_id name    city       
##         <dbl> <chr>   <chr>      
## 1           1 Alice   New York   
## 2           2 Bob     Los Angeles
## 3           3 Charlie Chicago

6. Anti Join (3 points) Perform an anti join with customers as the left table and orders as the right table.

q6<-anti_join(customers,orders)
## Joining with `by = join_by(customer_id)`

a. Which customers are in the result?
David and Eve
b. Explain what this result tells you about these customers.
Both David and Eve have customer IDs but no Orders to match
c. Display the result

print(q6)
## # A tibble: 2 × 3
##   customer_id name  city   
##         <dbl> <chr> <chr>  
## 1           4 David Houston
## 2           5 Eve   Phoenix

7. Practical Application (4 points) Imagine you’re analyzing customer behavior.

a. Which join would you use to find all customers, including those who haven’t placed any orders? Why?
I would use Left_join returns all records from the left table, and the matching records from the right table. Even if there is no match, it will still include the customer, but with the value “NA”
b. Which join would you use to find only the customers who have placed orders? Why?
I would use Inner_Join as it returns only the records where there is a match between the two tables
c. Write the R code for both scenarios.

    q7.1 <- left_join(customers, orders)
## Joining with `by = join_by(customer_id)`
    q7.2 <- inner_join(customers, orders)
## Joining with `by = join_by(customer_id)`

d. Display the result

  print(q7.1)
## # A tibble: 6 × 6
##   customer_id name    city        order_id product amount
##         <dbl> <chr>   <chr>          <dbl> <chr>    <dbl>
## 1           1 Alice   New York         101 Laptop    1200
## 2           2 Bob     Los Angeles      102 Phone      800
## 3           2 Bob     Los Angeles      104 Desktop   1500
## 4           3 Charlie Chicago          103 Tablet     300
## 5           4 David   Houston           NA <NA>        NA
## 6           5 Eve     Phoenix           NA <NA>        NA
  print(q7.2)
## # A tibble: 4 × 6
##   customer_id name    city        order_id product amount
##         <dbl> <chr>   <chr>          <dbl> <chr>    <dbl>
## 1           1 Alice   New York         101 Laptop    1200
## 2           2 Bob     Los Angeles      102 Phone      800
## 3           2 Bob     Los Angeles      104 Desktop   1500
## 4           3 Charlie Chicago          103 Tablet     300

Challenge Question (3 points)

Create a summary that shows each customer’s name, city, total number of orders, and total amount spent. Include all customers, even those without orders. Hint: You’ll need to use a combination of joins and group_by/summarize operations.

Challenge_Question <- customers %>%
    full_join(orders, by = "customer_id") %>%               
    group_by(customer_id, name, city) %>%                   
    summarize(
      total_orders = sum(!is.na(order_id)),                 
      total_amount_spent = sum(amount, na.rm = TRUE)) %>%         
    ungroup() 
## `summarise()` has grouped output by 'customer_id', 'name'. You can override
## using the `.groups` argument.
print(Challenge_Question)
## # A tibble: 7 × 5
##   customer_id name    city        total_orders total_amount_spent
##         <dbl> <chr>   <chr>              <int>              <dbl>
## 1           1 Alice   New York               1               1200
## 2           2 Bob     Los Angeles            2               2300
## 3           3 Charlie Chicago                1                300
## 4           4 David   Houston                0                  0
## 5           5 Eve     Phoenix                0                  0
## 6           6 <NA>    <NA>                   1                600
## 7           7 <NA>    <NA>                   1                150