The CData Excel Add-In for Microsoft Dataverse 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