diff --git a/htdocs/product/class/product.class.php b/htdocs/product/class/product.class.php
index 7973ab0db57..e9fcde9d67c 100644
--- a/htdocs/product/class/product.class.php
+++ b/htdocs/product/class/product.class.php
@@ -315,7 +315,7 @@ class Product extends CommonObject
 				$sql.= ", ".$this->status;
 				$sql.= ", ".$this->status_buy;
 				$sql.= ", '".$this->canvas."'";
-				$sql.= ", ".((! isset($this->finished) || $this->finished < 0)?'null':$this->finished);
+				$sql.= ", ".((empty($this->finished) || $this->finished < 0)?'null':$this->finished);
 				$sql.= ")";
 
 				dol_syslog(get_class($this)."::Create sql=".$sql);
@@ -463,7 +463,7 @@ class Product extends CommonObject
 
 		$sql.= ",tosell = " . $this->status;
 		$sql.= ",tobuy = " . $this->status_buy;
-		$sql.= ",finished = " . ((! isset($this->finished) || $this->finished < 0) ? "null" : $this->finished);
+		$sql.= ",finished = " . ((empty($this->finished) || $this->finished < 0) ? "null" : $this->finished);
 		$sql.= ",weight = " . ($this->weight!='' ? "'".$this->weight."'" : 'null');
 		$sql.= ",weight_units = " . ($this->weight_units!='' ? "'".$this->weight_units."'": 'null');
 		$sql.= ",length = " . ($this->length!='' ? "'".$this->length."'" : 'null');