diff --git a/htdocs/install/mysql/migration/15.0.0-16.0.0.sql b/htdocs/install/mysql/migration/15.0.0-16.0.0.sql
index 2933acd00d7..8eb37fb4f31 100644
--- a/htdocs/install/mysql/migration/15.0.0-16.0.0.sql
+++ b/htdocs/install/mysql/migration/15.0.0-16.0.0.sql
@@ -30,6 +30,8 @@
 -- -- VPGSQL8.2 SELECT dol_util_rebuild_sequences();
 
 
+ALTER TABLE llx_holiday ADD COLUMN nb_open_day double(24,8)     DEFAULT 0;
+
 -- Missing in v15 or lower
 
 ALTER TABLE llx_c_actioncomm MODIFY COLUMN libelle varchar(128);
diff --git a/htdocs/install/mysql/tables/llx_holiday.sql b/htdocs/install/mysql/tables/llx_holiday.sql
index 992f9502394..54d5525bd54 100644
--- a/htdocs/install/mysql/tables/llx_holiday.sql
+++ b/htdocs/install/mysql/tables/llx_holiday.sql
@@ -31,7 +31,8 @@ description    VARCHAR( 255 ) NOT NULL,
 date_debut     DATE NOT NULL,
 date_fin       DATE NOT NULL,
 halfday        integer DEFAULT 0,				-- 0=start morning and end afternoon, -1=start afternoon end afternoon, 1=start morning and end morning, 2=start afternoon and end morning
-statut         integer NOT NULL DEFAULT '1',
+nb_open_day    double(24,8)     DEFAULT 0,  -- denormalized number of open days of holiday. Not always set. More reliable when re-calculated with num_open_days(date_debut, date_fin, halfday).
+statut         integer NOT NULL DEFAULT 1,
 fk_validator   integer NOT NULL,				-- who should approve
 date_valid     DATETIME DEFAULT NULL,			-- date approval (both date valid and date_approval)
 fk_user_valid  integer DEFAULT NULL,			-- user approval (both user valid and user that approved)