Create anew column

I have adata included two tables 

Customer table included customer ID, customer name, state, city, country .

Orders table included order ID, sales, profits, customer ID, date .

I want to create a new column caculated the most 5 customers having sales .

First,you need to Create a relationship between the Customer and Orders tables using the customer ID column.

**Then create a measure for total sales:

Total Sales = SUM(Orders[sales])

and to rank customers by sales, you can use the following DAX measure:

Customer Sales Rank = 

RANKX(

    ALL(Customer),

    [Total Sales],

    DESC)

To create the new column identifying the top 5 customers, you can add a calculated column to the Customer table:

Top 5 Customer = 

IF(

    [Customer Sales Rank] <= 5,

    "Top 5 Customer",

    "Other")

To visualize this data:

Select a bar chart  vidual with Customer[customer_name] on the  x axis and [Total Sales] as the value in y axis

Add a visual level filter to the chart to only show where [Top 5 Customer] is "Top 5 Customer".

This will give you a bar chart of the top 5 customers by sales.