diff --git a/htdocs/install/mysql/migration/3.9.0-4.0.0.sql b/htdocs/install/mysql/migration/3.9.0-4.0.0.sql
index 7ce46730aa9..f793a6b471a 100644
--- a/htdocs/install/mysql/migration/3.9.0-4.0.0.sql
+++ b/htdocs/install/mysql/migration/3.9.0-4.0.0.sql
@@ -365,7 +365,7 @@ CREATE TABLE llx_c_accounting_category (
 
 ALTER TABLE llx_c_accounting_category ADD UNIQUE INDEX uk_c_accounting_category(code);
 UPDATE llx_accounting_account SET account_parent = '0' WHERE account_parent = '';
-ALTER TABLE llx_accounting_account MODIFY COLUMN account_parent integer;
+ALTER TABLE llx_accounting_account MODIFY COLUMN account_parent integer DEFAULT 0;
 
 
 DROP INDEX uk_bordereau_cheque ON llx_bordereau_cheque;