Migration to backfill LMSCourse.lms_api_course_id from existing grouping rows

lms/migrations/versions/9be518500f7d_backfill_lmscourse_api_lms_course_id.py

@@ -0,0 +1,42 @@
+"""Backfill LMSCourse.api_lms_course_id."""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "9be518500f7d"
+down_revision = "cf20e70211f9"
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+    conn.execute(
+        sa.text(
+            """
+        WITH backfill as (
+            -- Deduplicate "grouping" courses on authority_provided_id
+            SELECT DISTINCT ON (authority_provided_id)
+                authority_provided_id,
+                extra->'canvas'->>'custom_canvas_course_id' as api_id
+            FROM "grouping"
+            -- Pick only courses, not sections or groups
+            WHERE grouping.type ='course'
+            -- Pick only courses with an API ID
+            AND extra->'canvas'->>'custom_canvas_course_id' IS NOT NULL
+            -- Pick the most recent "grouping" there are duplicates
+            ORDER BY authority_provided_id, "grouping".updated desc
+        )
+        UPDATE lms_course
+        SET
+            lms_api_course_id = backfill.api_id
+        FROM backfill
+        WHERE
+        lms_course.h_authority_provided_id = backfill.authority_provided_id
+        -- We are already inserting rows in lms_course in the python code, leave those alone
+        AND lms_course.lms_api_course_id IS NULL
+    """
+        )
+    )
+
+
+def downgrade() -> None:
+    pass