special order by for mssql and db2

modules/activiti-engine/src/main/java/org/activiti/engine/impl/TaskQueryImpl.java

@@ -468,8 +468,16 @@ public class TaskQueryImpl extends AbstractQuery<TaskQuery, Task> implements Tas
     return orderBy(TaskQueryProperty.DUE_DATE);
   }
   
-  //results ////////////////////////////////////////////////////////////////
+  public String getMssqlOrDB2OrderBy() {
+    String specialOrderBy = super.getOrderBy();
+    if (specialOrderBy != null && specialOrderBy.length() > 0) {
+      specialOrderBy = specialOrderBy.replace("RES.", "TEMPRES_");
+    }
+    return specialOrderBy;
+  }
   
+  //results ////////////////////////////////////////////////////////////////
+
   public List<Task> executeList(CommandContext commandContext, Page page) {
     ensureVariablesInitialized();
     checkQueryOk();

modules/activiti-engine/src/main/java/org/activiti/engine/impl/db/DbSqlSessionFactory.java

@@ -96,7 +96,7 @@ public class DbSqlSessionFactory implements SessionFactory {
     databaseSpecificLimitBeforeStatements.put("db2", "SELECT SUB.* FROM (");
     databaseSpecificLimitAfterStatements.put("db2", ")RES ) SUB WHERE SUB.rnk >= #{firstRow} AND SUB.rnk < #{lastRow}");
     databaseSpecificLimitBetweenStatements.put("db2", ", row_number() over (ORDER BY ${orderBy}) rnk FROM ( select distinct RES.* ");
-    databaseOuterJoinLimitBetweenStatements.put("db2", ", row_number() over (ORDER BY ${orderBy}) rnk FROM ( select distinct ");
+    databaseOuterJoinLimitBetweenStatements.put("db2", ", row_number() over (ORDER BY ${mssqlOrDB2OrderBy}) rnk FROM ( select distinct ");
     databaseSpecificOrderByStatements.put("db2", "");
     databaseSpecificLimitBeforeNativeQueryStatements.put("db2", "SELECT SUB.* FROM ( select RES.* , row_number() over (ORDER BY ${orderBy}) rnk FROM (");
     addDatabaseSpecificStatement("db2", "selectExclusiveJobsToExecute", "selectExclusiveJobsToExecute_integerBoolean");
@@ -118,7 +118,7 @@ public class DbSqlSessionFactory implements SessionFactory {
     databaseSpecificLimitBeforeStatements.put("mssql", "SELECT SUB.* FROM (");
     databaseSpecificLimitAfterStatements.put("mssql", ")RES ) SUB WHERE SUB.rnk >= #{firstRow} AND SUB.rnk < #{lastRow}");
     databaseSpecificLimitBetweenStatements.put("mssql", ", row_number() over (ORDER BY ${orderBy}) rnk FROM ( select distinct RES.* ");
-    databaseOuterJoinLimitBetweenStatements.put("mssql", ", row_number() over (ORDER BY ${orderBy}) rnk FROM ( select distinct ");
+    databaseOuterJoinLimitBetweenStatements.put("mssql", ", row_number() over (ORDER BY ${mssqlOrDB2OrderBy}) rnk FROM ( select distinct ");
     databaseSpecificOrderByStatements.put("mssql", "");
     databaseSpecificLimitBeforeNativeQueryStatements.put("mssql", "SELECT SUB.* FROM ( select RES.* , row_number() over (ORDER BY ${orderBy}) rnk FROM (");
     addDatabaseSpecificStatement("mssql", "selectExclusiveJobsToExecute", "selectExclusiveJobsToExecute_integerBoolean");