diff --git a/01-diff-view.sql b/01-diff-view.sql
new file mode 100644
index 0000000..4e01b8c
--- /dev/null
+++ b/01-diff-view.sql
@@ -0,0 +1,2 @@
+DROP VIEW IF EXISTS chiffres_diff;
+CREATE VIEW IF NOT EXISTS chiffres_diff  AS SELECT date, code_INSEE, nombre - LAG(nombre) OVER (PARTITION BY code_INSEE ORDER BY date) AS nombre FROM chiffres;