diff --git a/process/Attribute_lib/process.js b/process/Attribute_lib/process.js
index 851b632e9e90f9fa5ba4ad589353f8916b6c6cbb..aec8585c20e9f9df05f21bb2958494fdeb9970be 100644
--- a/process/Attribute_lib/process.js
+++ b/process/Attribute_lib/process.js
@@ -1,3 +1,4 @@
+import("Contact_lib");
 import("Util_lib");
 import("Employee_lib");
 import("KeywordData_lib");
@@ -12,6 +13,7 @@ import("system.project");
 import("system.entities");
 import("Sql_lib");
 import("Keyword_lib");
+import("KeywordRegistry_basic");
 
 /**
  * Provides functions for the work with attributes,<br>
@@ -1244,6 +1246,62 @@ Object.assign(AttributeTypes.OBJECTSELECTION, {
     contentType: "UNKNOWN",
     databaseField: "ID_VALUE",
     useLookup: true,
+    getDisplayValueSql: function (pAttributeData)
+    {
+        /* This switch-case isn't a great solution regarding the entity model, but there is currently no other solution to resolve
+         * these display values when grouping by attributes. Don't copy or re-use this!
+         */
+        var idField = "AB_ATTRIBUTERELATION." + this.databaseField;
+        var sqlMask = new SqlMaskingUtils();
+        switch (pAttributeData.dropDownDefinition)
+        {
+            case "Activity_entity":
+                return newSelect("ACTIVITY.SUBJECT").from("ACTIVITY").where("ACTIVITY.ACTIVITYID = " + idField);
+            case "Attribute_entity":
+                return newSelect("AB_ATTRIBUTE.ATTRIBUTE_NAME").from("AB_ATTRIBUTE").where("AB_ATTRIBUTE.AB_ATTRIBUTEID = " + idField);
+            case "BulkMail_entity":
+                return newSelect("BULKMAIL.NAME").from("BULKMAIL").where("BULKMAIL.BULKMAILID = " + idField);
+            case "Campaign_entity":
+                return newSelect("CAMPAIGN.NAME").from("CAMPAIGN").where("CAMPAIGN.CAMPAIGNID = " + idField);
+            case "CampaignStep_entity":
+                return newSelect("CAMPAIGNSTEP.NAME").from("CAMPAIGNSTEP").where("CAMPAIGNSTEP.CAMPAIGNSTEPID = " + idField);
+            case "AnyContact_entity":
+            case "Person_entity":
+                return "(" + ContactUtils.getResolvingDisplaySubSql(idField) + ")";
+            case "Organisation_entity":
+                return newSelect("ORGANISATION.NAME").from("ORGANISATION")
+                    .join("CONTACT", "CONTACT.ORGANISATION_ID = ORGANISATION.ORGANISATIONID and CONTACT.PERSON_ID is null")
+                    .where("CONTACT.CONTACTID = " + idField);
+            case "Contract_entity":
+                return newSelect(sqlMask.concatWithSeparator([
+                            KeywordUtils.getResolvedTitleSqlPart($KeywordRegistry.contractType(), "CONTRACT.CONTRACTTYPE"), 
+                            "CONTRACT.CONTRACTCODE"
+                        ], " | ", false))
+                    .from("CONTRACT").where("CONTRACT.CONTRACTID = " + idField);
+            case "DocumentTemplate_entity":
+                return newSelect("DOCUMENTTEMPLATE.NAME").from("DOCUMENTTEMPLATE").where("DOCUMENTTEMPLATE.DOCUMENTTEMPLATEID = " + idField);
+            case "Language_entity":
+                return newSelect("AB_LANGUAGE.NAME_LATIN").from("AB_LANGUAGE").where("AB_LANGUAGE.ISO3 = " + idField);
+            case "Offer_entity":
+                return newSelect(sqlMask.concatWithSeparator(["OFFER.OFFERCODE", "OFFER.VERSNR"], " - ", false))
+                    .from("OFFER").where("OFFER.OFFERID = " + idField);
+            case "Order_entity":
+                return newSelect("SALESORDER.SALESORDERCODE").from("SALESORDER").where("SALESORDER.SALESORDERID = " + idField);
+            case "Product_entity":
+                return newSelect("PRODUCT.PRODUCTNAME").from("PRODUCT").where("PRODUCT.PRODUCTID = " + idField);
+            case "Salesproject_entity":
+                return newSelect(sqlMask.concatWithSeparator(["SALESPROJECT.PROJECTCODE", "SALESPROJECT.PROJECTTITLE"], " | ", false))
+                    .from("SALESPROJECT").where("SALESPROJECT.SALESPROJECTID = " + idField);
+            case "SerialLetter_entity":
+                return newSelect("SERIALLETTER.TITLE").from("SERIALLETTER").where("SERIALLETTER.SERIALLETTERID = " + idField);
+            case "SupportTicket_entity":
+                return newSelect("TASK.SUBJECT").from("TICKET").leftJoin("TASK", "TICKET.TASK_ID = TASK.TASKID").where("TICKET.TICKETID = " + idField);
+            case "Task_entity":
+                return newSelect("TASK.SUBJECT").from("TASK").where("TASK.TASKID = " + idField);
+            default:
+                return "''";
+        }
+    },
     getViewValue: function (pValue, pModule)
         {
             if (pValue)
diff --git a/process/Sql_lib/process.js b/process/Sql_lib/process.js
index 2e20ae0d4b062631b3b3b76ba9aa498498258ce5..99ac7c2ae77834fabf6ab776518fb3e13df46da7 100644
--- a/process/Sql_lib/process.js
+++ b/process/Sql_lib/process.js
@@ -3860,6 +3860,8 @@ SqlMaskingUtils.prototype.isNull = function (pField, pReplacement)
 {
     if (pReplacement == undefined)
         pReplacement = "''";
+    if (pField instanceof SqlBuilder)
+        pField = "(" + pField.toString() + ")";
     switch (this.dbType) 
     {
         case db.DBTYPE_SQLSERVER2000: