Select all rows from joined with multiple conditions tables with null values

Question

I want to join two tables, Sales and Budget.

Sales table columns:

| Customer | Period | Sales |

Budget table columns:

| Customer | Period | SaleBudget |

Sales table has data for periods 1, 2, and 3. Budget has data for periods 1-12. When I try to run below query I get only data for periods from Sales table matched with Budget table. But my goal is to get all data from both tables. Could you give me a hint how to change query?

Select s.Customer, b.SaleBudget, s.Sales from Sales s
full outer join Budget b on b.Customer = s.Customer and b.Period = s.Period

Answer 1

When you use left join its join the rows that are same in

b.Customer = s.Customer and b.Period = s.Period

if you want have all of the rows you shouldn't use left join; The LEFT JOIN keyword returns all records from the left table (table1), and the matching records from the right table (table2); there is not any way that get some data matching and some data Inconsistency in one shape.