OLINGO-960: returning null on the missing alias value in query
diff --git a/lib/server-core/src/main/java/org/apache/olingo/server/core/uri/parser/ExpressionParser.java b/lib/server-core/src/main/java/org/apache/olingo/server/core/uri/parser/ExpressionParser.java
index c9f8b21..23fd8a4 100644
--- a/lib/server-core/src/main/java/org/apache/olingo/server/core/uri/parser/ExpressionParser.java
+++ b/lib/server-core/src/main/java/org/apache/olingo/server/core/uri/parser/ExpressionParser.java
@@ -339,8 +339,7 @@
         return new AliasImpl(name,
             ParserHelper.parseAliasValue(name, null, true, true, edm, referringType, aliases));
       } else {
-        throw new UriValidationException("Alias '" + name + "' not found.",
-            UriValidationException.MessageKeys.MISSING_ALIAS, name);
+        return new AliasImpl(name, null);
       }
     }
 
diff --git a/lib/server-test/src/test/java/org/apache/olingo/server/core/uri/parser/TestFullResourcePath.java b/lib/server-test/src/test/java/org/apache/olingo/server/core/uri/parser/TestFullResourcePath.java
index 8aa3172..d60e6c3 100644
--- a/lib/server-test/src/test/java/org/apache/olingo/server/core/uri/parser/TestFullResourcePath.java
+++ b/lib/server-test/src/test/java/org/apache/olingo/server/core/uri/parser/TestFullResourcePath.java
@@ -5846,11 +5846,11 @@
     testUri.runEx("ESAllPrim(PropertyInt16=@p1)", "@p1='ewe")
         .isExSyntax(UriParserSyntaxException.MessageKeys.SYNTAX);
     testFilter.runOnETKeyNavEx("PropertyInt16 gt @alias")
-        .isExValidation(UriValidationException.MessageKeys.MISSING_ALIAS);
+        .isInAliasToValueMap("@alias", null);
     testFilter.runOnETKeyNavEx("PropertyInt16 gt @alias&@alias=@alias")
-        .isExValidation(UriValidationException.MessageKeys.MISSING_ALIAS);
+      .isInAliasToValueMap("@alias", "@alias");
     testFilter.runOnETKeyNavEx("@alias&@alias=@alias2&@alias2=true or @alias")
-        .isExValidation(UriValidationException.MessageKeys.MISSING_ALIAS);
+      .isInAliasToValueMap("@alias", "@alias2");
   }
 
   @Test