Add fct_order_items model

models/example/fct_order_items.sql

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+{# 
+create a `fct_order_items` table joining orders to customers to get the 
+`order_date` and `email` and `customer_id` on the order table
+#}
+with source_1 as (
+
+    select * from {{ ref('orders_upload') }}
+
+),
+
+source_2 as (
+
+    select * from {{ ref('customers_upload') }}
+
+)
+
+final as (
+
+    select
+        source_1.created_at,
+        source_2.email,
+        source_2.customer_id,
+
+    from source_1
+
+    left join source_2 on source_1.customer_id  = source_2.id
+
+)
+
+select * from renamed

models/example/order_calculations.sql

@@ -0,0 +1,30 @@
+with source1 as (
+
+    select * from {{ ref('customers_upload') }}
+
+),
+
+source2 as (
+
+    select * from {{ ref('orders_upload') }}
+),
+
+calc as (
+
+    select 
+        source1.id as customer_id, 
+        lag(source2.created_at, 1) [ignore nulls] 
+        over (partition by source1.id
+        order by source2.created_at desc) as created_at_prev,
+        created_at
+    from source1
+
+    inner join source2
+
+            on source1.id = source2.customer_id
+
+)
+
+    select 
+        datediff(month, created_at, created_at_prev) as months_since_prior_order
+    from calc