The CData Cmdlets PowerShell Module for Highrise 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 charges.amount, customers.email FROM customers INNER JOIN charges ON charges.customerId = customers.id

Left Join

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

SELECT charges.amount, customers.email FROM customers LEFT JOIN charges ON charges.customerId = customers.id