Merge Statements

Merge statements unify concepts from different sources, allowing them to be queried together. This is useful when the same logical concept exists in multiple namespaces.

Syntax

merge_statement: "merge" WILDCARD_IDENTIFIER "into" SHORTHAND_MODIFIER? WILDCARD_IDENTIFIER

Basic Merge

Merge one concept into another:

import sales.customer as sales_customer;
import support.customer as support_customer;
merge sales_customer.id into support_customer.id;

After merging, queries can join data across both sources using the merged concept.

Wildcard Merge

Use wildcards to merge multiple concepts at once:

merge sales.* into main.*;

This merges all matching concepts from the sales namespace into the main namespace.

Partial Modifier

Use ~ to mark the merge as partial (the merged concept has a subset of values of the full concept).

Tips

This is very common for blending into a date dimension, for example - you may not have an order on every day.

merge sales.customer.id into ~main.customer.id;

Example

import web_orders as web;
import store_orders as store;
# Merge order concepts so we can query across channels
merge web.order.id into store.order.id;
merge web.order.date into store.order.date;
merge web.order.total into store.order.total;
select
    store.order.date,
    sum(store.order.total) -> combined_sales
;