Joins

A join connects records from two JSON sources.

Bare join keeps both sides

Use inner join, left join, or right join when you want that specific behavior. A bare join is a full outer join and keeps unmatched rows from both sources.

select {orderId: o.id, customer: c.name}
from 'orders.json' as o
inner join 'customers.json' as c on o.customerId = c.id

The on condition says how the records are related. Aliases such as o and c keep the fields easy to identify.

Join types

Syntax	Rows kept
inner join	Matching combinations only.
left join	Matches and unmatched rows from the left source.
right join	Matches and unmatched rows from the right source.
join	Matches and unmatched rows from both sources.

For an unmatched aliased source, the alias has a null value. Its projected fields are left out of the result.

One-to-many matches

JQL checks every left record against every right record. If one customer has several matching orders, every matching pair becomes a result row.

Multiple joins

Write joins in dependency order. A later join can use an alias introduced earlier:

from 'orders.json' as o
inner join 'customers.json' as c on o.customerId = c.id
inner join 'regions.json' as r on c.regionId = r.id

Joined sources may also use nested source paths. where runs after all joins are complete.