The CData ADO.NET Provider for Microsoft Dynamics 365 Business Central supports standard SQL joins like the following examples.

Inner Join

An inner join selects only rows from both tables that match the join condition:

SELECT Accounts.Name, Contracts.ContractNumber FROM Accounts, Contracts WHERE Accounts.AccountId=Contracts._AccountId_Value

Left Join

A left join selects all rows in the FROM table and only matching rows in the JOIN table:

SELECT Accounts.Name, Contracts.ContractNumber FROM Accounts LEFT OUTER JOIN Contracts ON Accounts.AccountId=Contracts._AccountId_Value