The CData Cmdlets PowerShell Module for Acumatica 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 Customer.CustomerName, MainContact.DisplayName FROM Customer, Customer_Maincontact WHERE Customer.CustomerID=Customer_Maincontact.ParentCustomerID

Left Join

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

SELECT Groups.displayName, Conversations.Topic FROM Groups LEFT OUTER JOIN Conversations ON Groups.Id=Conversations.GroupId