--- a/cubicweb/rset.py	Thu Mar 12 15:38:51 2020 +0100
+++ b/cubicweb/rset.py	Fri Mar 20 14:34:07 2020 +0100
@@ -42,7 +42,7 @@
     :param rql: the original RQL query string
     """
 
-    def __init__(self, results, rql, args=None, description=None):
+    def __init__(self, results, rql, args=None, description=None, variables=None):
         self.rows = results
         self.rowcount = results and len(results) or 0
         # original query and arguments
@@ -54,6 +54,7 @@
             self.description = []
         else:
             self.description = description
+        self.variables = variables if variables is not None else []
         # set to (limit, offset) when a result set is limited using the
         # .limit method
         self.limited = None

--- a/cubicweb/server/querier.py	Thu Mar 12 15:38:51 2020 +0100
+++ b/cubicweb/server/querier.py	Fri Mar 20 14:34:07 2020 +0100
@@ -25,7 +25,8 @@
 
 from rql import RQLSyntaxError, CoercionError
 from rql.stmts import Union
-from rql.nodes import ETYPE_PYOBJ_MAP, etype_from_pyobj, Relation, Exists, Not
+from rql.nodes import ETYPE_PYOBJ_MAP, etype_from_pyobj, Relation, Exists, Not,\
+    VariableRef, Constant
 from yams import BASE_TYPES
 
 from cubicweb import ValidationError, Unauthorized, UnknownEid, QueryError
@@ -579,6 +580,7 @@
 
         # build a description for the results if necessary
         descr = ()
+        variables = None
         if build_descr:
             if rqlst.TYPE == 'select':
                 # sample selection
@@ -588,6 +590,8 @@
                     solution = rqlst.children[0].solutions[0]
                     description = _make_description(selected, args, solution)
                     descr = RepeatList(len(results), tuple(description))
+                    variables = [self._get_projected_name(projected, rqlst.children[0].stinfo)
+                                 for projected in selected]
                 else:
                     # hard, delegate the work :o)
                     descr = manual_build_descr(cnx, rqlst, args, results)
@@ -605,12 +609,24 @@
         emit_to_debug_channel("rql", query_debug_informations)
 
         # return a result set object
-        return ResultSet(results, rql, args, descr)
+        return ResultSet(results, rql, args, descr, variables)
 
     # these are overridden by set_log_methods below
     # only defining here to prevent pylint from complaining
     info = warning = error = critical = exception = debug = lambda msg,*a,**kw: None
 
+    @staticmethod
+    def _get_projected_name(projected, stinfo):
+        if isinstance(projected, VariableRef):
+            return projected.name
+        elif isinstance(projected, Constant):
+            if stinfo['rewritten'] is None:
+                return str(projected)
+            for name, value in stinfo['rewritten'].items():
+                if [projected] == value:
+                    return name
+        return str(projected)
+
 
 class RQLCache(object):
 

--- a/cubicweb/server/test/unittest_querier.py	Thu Mar 12 15:38:51 2020 +0100
+++ b/cubicweb/server/test/unittest_querier.py	Fri Mar 20 14:34:07 2020 +0100
@@ -1626,7 +1626,6 @@
                              'X in_state S, S name SN')
         self.assertEqual(rset.rows, [[peid]])
 
-
     def test_nonregr_sql_cache(self):
         # different SQL generated when 'name' is None or not (IS NULL).
         self.assertFalse(self.qexecute('Any X WHERE X is CWEType, X name %(name)s',
@@ -1634,6 +1633,24 @@
         self.assertTrue(self.qexecute('Any X WHERE X is CWEType, X name %(name)s',
                                       {'name': 'CWEType'}))
 
+    def test_variables_in_rset_for_select(self):
+        rset = self.qexecute('Any X WHERE X is CWUser, X eid %(x)s', {'x': self.ueid})
+        self.assertEqual(rset.variables, ['X'])
+
+    def test_only_selected_variables_in_rset(self):
+        rset = self.qexecute('Any X,Y WHERE X is Personne, Y is Personne, '
+                             'X nom XD, Y nom XD, X eid Z, Y eid > Z')
+        # Z is not selected
+        self.assertEqual(rset.variables, ['X', 'Y'])
+
+    def test_no_variables_in_rset(self):
+        rset = self.qexecute('Any COUNT(X) WHERE X is CWUser')
+        self.assertEqual(rset.variables, ['COUNT(X)'])
+
+    def test_mixed_projection_in_rset(self):
+        rset = self.qexecute('Any X,COUNT(X) WHERE X is CWUser')
+        self.assertEqual(rset.variables, ['X', 'COUNT(X)'])
+
 
 class NonRegressionTC(CubicWebTC):