How to Duplicate SQL Inner Join Logic to Power BI (Same Table)

Basket analysis: 

if you are looking for basket analysis, after checking out the latimeria links, you can also do "Disconnected tables" method for doing Basket analysis, assuming you have star schema type of model:

• Create Disconnected tables:
  Create a copy of slicer table for all slicers you need and make sure they are not connected in your model! Say, Products Slicer, Customers Slicer table.
  In Power Query, you can create as reference. Most importating thing is disconnect them in the model view. 
  In DAX, you can create the table as Products Slicer = Products. Most important thing is disconnect this slicer tables in the model view.
• Add a measure per your needs

Say, 

Sales = 
//get list of all customers of selected products
VAR __isProductFiltered = ISFILTERED ( 'Products Slicer'[Product] ) //is product has filter
VAR __isCustomerFiltered = ISFILTERED ( 'Customers Slicer'[Customer] ) //is customer has filter
VAR __isNothingSelected = NOT __isProductFiltered && NOT __isCustomerFiltered //is both customer and product are not selected
VAR __getProducts = ( NOT ( __isCustomerFiltered && NOT __isProductFiltered ) ) || __isNothingSelected 
VAR __getCustomers = ( NOT ( __isProductFiltered && NOT __isCustomerFiltered ) ) || __isNothingSelected
VAR __customersforSelectedProduct = 
//IF ( __getProducts,
    SUMMARIZE ( 
        FILTER ( 
            Sales,
            Sales[ProductKey] IN VALUES ( 'Products Slicer'[ProductKey] ) 
        ),
        Sales[ProductKey],
        Sales[CustomerKey]
    )
//get list of all products of selected customers
VAR __productsforSelectedCustomer = 
    SUMMARIZE ( 
        FILTER ( 
            Sales,
            Sales[CustomerKey] IN VALUES ( 'Customers Slicer'[CustomerKey] ) 
        ),
        Sales[ProductKey],
        Sales[CustomerKey]
    )

//combine both table and get the distinct customers and product 
VAR __filterSales = 
DISTINCT (
    UNION ( 
        FILTER ( __customersforSelectedProduct, __getProducts ),
        FILTER ( __productsforSelectedCustomer, __getCustomers )
    )
)
RETURN
//filter sales for cutomers and products
CALCULATE ( 
    SUM ( Sales[Total Sales Amount] ), 
    TREATAS ( __filterSales, Sales[ProductKey], Sales[CustomerKey] ) 
)

explained in this link...

https://perytus.com/2021/03/23/multiple-slicers-use-or-condition-to-visualize-data/

Thank you, I appreciate the information. Not something I've done before but first time for everything. Cheers