diff --git a/sale_global_discount/__init__.py b/sale_global_discount/__init__.py
index 0650744f6bc..79b7e880446 100644
--- a/sale_global_discount/__init__.py
+++ b/sale_global_discount/__init__.py
@@ -1 +1,2 @@
 from . import models
+from .hooks import _pre_init_global_discount_fields
diff --git a/sale_global_discount/__manifest__.py b/sale_global_discount/__manifest__.py
index eef8551a07c..458331b06b8 100644
--- a/sale_global_discount/__manifest__.py
+++ b/sale_global_discount/__manifest__.py
@@ -12,4 +12,5 @@
     "data": ["views/sale_order_views.xml", "views/report_sale_order.xml"],
     "application": False,
     "installable": True,
+    "pre_init_hook": "_pre_init_global_discount_fields",
 }
diff --git a/sale_global_discount/hooks.py b/sale_global_discount/hooks.py
new file mode 100644
index 00000000000..7738bfe0612
--- /dev/null
+++ b/sale_global_discount/hooks.py
@@ -0,0 +1,40 @@
+from odoo.tools.sql import column_exists
+
+
+def _pre_init_global_discount_fields(cr):
+    if not column_exists(cr, "sale_order", "amount_global_discount"):
+        cr.execute(
+            """
+                ALTER TABLE "sale_order"
+                ADD COLUMN "amount_global_discount" double precision DEFAULT 0
+            """
+        )
+        cr.execute(
+            """
+        ALTER TABLE "sale_order" ALTER COLUMN "amount_global_discount" DROP DEFAULT
+        """
+        )
+    if not column_exists(cr, "sale_order", "amount_untaxed_before_global_discounts"):
+        cr.execute(
+            """
+                ALTER TABLE "sale_order"
+                ADD COLUMN "amount_untaxed_before_global_discounts" double precision
+            """
+        )
+        cr.execute(
+            """
+        update sale_order set amount_untaxed_before_global_discounts = amount_untaxed
+        """
+        )
+    if not column_exists(cr, "sale_order", "amount_total_before_global_discounts"):
+        cr.execute(
+            """
+                ALTER TABLE "sale_order"
+                ADD COLUMN "amount_total_before_global_discounts" double precision
+            """
+        )
+        cr.execute(
+            """
+        update sale_order set amount_total_before_global_discounts = amount_total
+        """
+        )