diff --git a/src/com/amarsoft/app/flow/FlowAction.java b/src/com/amarsoft/app/flow/FlowAction.java
index 494cbb258..04587d97f 100644
--- a/src/com/amarsoft/app/flow/FlowAction.java
+++ b/src/com/amarsoft/app/flow/FlowAction.java
@@ -691,7 +691,7 @@ public class FlowAction {
 					sql.setOriginalSql(sql.getOriginalSql().replaceAll("¡÷", ":"));
 					sql.setRunSql(sql.getRunSql().replaceAll("¡÷", ":"));
 					tran.executeSQL(sql);
-					sql = new SqlObject("update user_task_info set task_number = nvl(task_number, 0) + 1 "
+					sql = new SqlObject("update user_task_info set task_number = task_number + 1 "
 							+ " where userid = '" + AssignmentId + "' and roleid = '" + curRole + "'");
 					tran.executeSQL(sql);
 				} else {
@@ -703,8 +703,8 @@ public class FlowAction {
 				sql.setOriginalSql(sql.getOriginalSql().replaceAll("¡÷", ":"));
 				sql.setRunSql(sql.getRunSql().replaceAll("¡÷", ":"));
 				tran.executeSQL(sql);
-				sql = new SqlObject("update user_task_info set task_number = nvl(task_number, 0) - 1 "
-						+ " where userid = '" + userID + "' and roleid = '" + curRole + "'");
+				sql = new SqlObject("update user_task_info set task_number = task_number - 1 "
+						+ " where userid = '" + userID + "' and roleid = '" + curRole + "' and task_number >=1 ");
 				tran.executeSQL(sql);
 			}
 		}