feat: add stagingquery quickstart for purchases

Co-authored-by: Thomas Chow <[email protected]>

Author: tchow-zlai

api/py/test/sample/group_bys/quickstart/purchases.py

@@ -15,6 +15,7 @@
 from ai.chronon.api.ttypes import Source, EventSource
 from ai.chronon.query import Query, select
 from ai.chronon.group_by import GroupBy, Aggregation, Operation
+from ai.chronon.api.ttypes import StagingQuery, MetaData
 
 """
 This GroupBy aggregates metrics about a user's previous purchases in various windows.
@@ -67,3 +68,25 @@
         ),
     ],
 )
+
+
+query = """
+SELECT
+    ts,
+    ds,
+    purchase_id,
+    user_id,
+    product_id,
+    purchase_price
+FROM data.purchases
+WHERE ds BETWEEN '{{ start_date }}' AND '{{ end_date }}'
+"""
+
+staging_query = StagingQuery(
+    query=query,
+    startPartition="2023-10-31",
+    metaData=MetaData(
+        name='purchases_staging_query',
+        outputNamespace="data"
+    )
+)