diff --git a/src/engine/Bind.cpp b/src/engine/Bind.cpp
index bdccf1448..276f04e9f 100644
--- a/src/engine/Bind.cpp
+++ b/src/engine/Bind.cpp
@@ -5,7 +5,7 @@
 #include "Bind.h"
 
 #include "engine/CallFixedSize.h"
-#include "engine/ExistsScan.h"
+#include "engine/ExistsJoin.h"
 #include "engine/QueryExecutionTree.h"
 #include "engine/sparqlExpressions/SparqlExpression.h"
 #include "engine/sparqlExpressions/SparqlExpressionGenerators.h"
@@ -16,7 +16,7 @@
 Bind::Bind(QueryExecutionContext* qec,
            std::shared_ptr<QueryExecutionTree> subtree, parsedQuery::Bind b)
     : Operation(qec), _subtree(std::move(subtree)), _bind(std::move(b)) {
-  _subtree = ExistsScan::addExistsScansToSubtree(
+  _subtree = ExistsJoin::addExistsScansToSubtree(
       _bind._expression, std::move(_subtree), getExecutionContext(),
       cancellationHandle_);
 }
diff --git a/src/engine/CMakeLists.txt b/src/engine/CMakeLists.txt
index c724a8fb3..a3750a07e 100644
--- a/src/engine/CMakeLists.txt
+++ b/src/engine/CMakeLists.txt
@@ -14,5 +14,5 @@ add_library(engine
         CartesianProductJoin.cpp TextIndexScanForWord.cpp TextIndexScanForEntity.cpp
         TextLimit.cpp LazyGroupBy.cpp GroupByHashMapOptimization.cpp SpatialJoin.cpp
         CountConnectedSubgraphs.cpp SpatialJoinAlgorithms.cpp PathSearch.cpp ExecuteUpdate.cpp
-        Describe.cpp ExistsScan.cpp)
+        Describe.cpp ExistsJoin.cpp)
 qlever_target_link_libraries(engine util index parser sparqlExpressions http SortPerformanceEstimator Boost::iostreams s2)
diff --git a/src/engine/ExistsScan.cpp b/src/engine/ExistsJoin.cpp
similarity index 90%
rename from src/engine/ExistsScan.cpp
rename to src/engine/ExistsJoin.cpp
index c416d1dc4..d8d3f564d 100644
--- a/src/engine/ExistsScan.cpp
+++ b/src/engine/ExistsJoin.cpp
@@ -2,7 +2,7 @@
 //                  Chair of Algorithms and Data Structures.
 //  Author: Johannes Kalmbach <kalmbach@cs.uni-freiburg.de>
 
-#include "engine/ExistsScan.h"
+#include "engine/ExistsJoin.h"
 
 #include "engine/QueryPlanner.h"
 #include "engine/sparqlExpressions/ExistsExpression.h"
@@ -10,7 +10,7 @@
 #include "util/JoinAlgorithms/JoinAlgorithms.h"
 
 // _____________________________________________________________________________
-ExistsScan::ExistsScan(QueryExecutionContext* qec,
+ExistsJoin::ExistsJoin(QueryExecutionContext* qec,
                        std::shared_ptr<QueryExecutionTree> left,
                        std::shared_ptr<QueryExecutionTree> right,
                        Variable existsVariable)
@@ -24,16 +24,16 @@ ExistsScan::ExistsScan(QueryExecutionContext* qec,
 }
 
 // _____________________________________________________________________________
-string ExistsScan::getCacheKeyImpl() const {
+string ExistsJoin::getCacheKeyImpl() const {
   return absl::StrCat("EXISTS SCAN left: ", left_->getCacheKey(),
                       " right: ", right_->getCacheKey());
 }
 
 // _____________________________________________________________________________
-string ExistsScan::getDescriptor() const { return "EXISTS scan"; }
+string ExistsJoin::getDescriptor() const { return "EXISTS scan"; }
 
 // ____________________________________________________________________________
-VariableToColumnMap ExistsScan::computeVariableToColumnMap() const {
+VariableToColumnMap ExistsJoin::computeVariableToColumnMap() const {
   auto res = left_->getVariableColumns();
   AD_CONTRACT_CHECK(
       !res.contains(existsVariable_),
@@ -43,18 +43,18 @@ VariableToColumnMap ExistsScan::computeVariableToColumnMap() const {
 }
 
 // ____________________________________________________________________________
-size_t ExistsScan::getResultWidth() const {
+size_t ExistsJoin::getResultWidth() const {
   // We add one column to the input.
   return left_->getResultWidth() + 1;
 }
 
 // ____________________________________________________________________________
-vector<ColumnIndex> ExistsScan::resultSortedOn() const {
+vector<ColumnIndex> ExistsJoin::resultSortedOn() const {
   return left_->resultSortedOn();
 }
 
 // ____________________________________________________________________________
-float ExistsScan::getMultiplicity(size_t col) {
+float ExistsJoin::getMultiplicity(size_t col) {
   if (col < getResultWidth() - 1) {
     return left_->getMultiplicity(col);
   }
@@ -64,18 +64,18 @@ float ExistsScan::getMultiplicity(size_t col) {
 }
 
 // ____________________________________________________________________________
-uint64_t ExistsScan::getSizeEstimateBeforeLimit() {
+uint64_t ExistsJoin::getSizeEstimateBeforeLimit() {
   return left_->getSizeEstimate();
 }
 
 // ____________________________________________________________________________
-size_t ExistsScan::getCostEstimate() {
+size_t ExistsJoin::getCostEstimate() {
   return left_->getCostEstimate() + right_->getCostEstimate() +
          left_->getSizeEstimate() + right_->getSizeEstimate();
 }
 
 // ____________________________________________________________________________
-ProtoResult ExistsScan::computeResult([[maybe_unused]] bool requestLaziness) {
+ProtoResult ExistsJoin::computeResult([[maybe_unused]] bool requestLaziness) {
   auto leftRes = left_->getResult();
   auto rightRes = right_->getResult();
   const auto& left = leftRes->idTable();
@@ -139,7 +139,7 @@ ProtoResult ExistsScan::computeResult([[maybe_unused]] bool requestLaziness) {
 }
 
 // _____________________________________________________________________________
-std::shared_ptr<QueryExecutionTree> ExistsScan::addExistsScansToSubtree(
+std::shared_ptr<QueryExecutionTree> ExistsJoin::addExistsScansToSubtree(
     const sparqlExpression::SparqlExpressionPimpl& expression,
     std::shared_ptr<QueryExecutionTree> subtree, QueryExecutionContext* qec,
     const ad_utility::SharedCancellationHandle& cancellationHandle) {
@@ -158,7 +158,7 @@ std::shared_ptr<QueryExecutionTree> ExistsScan::addExistsScansToSubtree(
     auto pq = exists.argument();
     auto tree =
         std::make_shared<QueryExecutionTree>(qp.createExecutionTree(pq));
-    subtree = ad_utility::makeExecutionTree<ExistsScan>(
+    subtree = ad_utility::makeExecutionTree<ExistsJoin>(
         qec, std::move(subtree), std::move(tree), exists.variable());
   }
   return subtree;
diff --git a/src/engine/ExistsScan.h b/src/engine/ExistsJoin.h
similarity index 95%
rename from src/engine/ExistsScan.h
rename to src/engine/ExistsJoin.h
index dbd947d30..9b9c7483c 100644
--- a/src/engine/ExistsScan.h
+++ b/src/engine/ExistsJoin.h
@@ -7,7 +7,7 @@
 #include "engine/Operation.h"
 #include "engine/QueryExecutionTree.h"
 
-class ExistsScan : public Operation {
+class ExistsJoin : public Operation {
  private:
   std::shared_ptr<QueryExecutionTree> left_;
   std::shared_ptr<QueryExecutionTree> right_;
@@ -19,7 +19,7 @@ class ExistsScan : public Operation {
   std::vector<std::array<ColumnIndex, 2>> _matchedColumns;
 
  public:
-  ExistsScan(QueryExecutionContext* qec,
+  ExistsJoin(QueryExecutionContext* qec,
              std::shared_ptr<QueryExecutionTree> left,
              std::shared_ptr<QueryExecutionTree> right,
              Variable existsVariable);
diff --git a/src/engine/Filter.cpp b/src/engine/Filter.cpp
index ff8edc1fc..9da7c1272 100644
--- a/src/engine/Filter.cpp
+++ b/src/engine/Filter.cpp
@@ -10,7 +10,7 @@
 
 #include "backports/algorithm.h"
 #include "engine/CallFixedSize.h"
-#include "engine/ExistsScan.h"
+#include "engine/ExistsJoin.h"
 #include "engine/QueryExecutionTree.h"
 #include "engine/QueryPlanner.h"
 #include "engine/sparqlExpressions/SparqlExpression.h"
@@ -31,7 +31,7 @@ Filter::Filter(QueryExecutionContext* qec,
     : Operation(qec),
       _subtree(std::move(subtree)),
       _expression{std::move(expression)} {
-  _subtree = ExistsScan::addExistsScansToSubtree(
+  _subtree = ExistsJoin::addExistsScansToSubtree(
       _expression, std::move(_subtree), getExecutionContext(),
       cancellationHandle_);
   setPrefilterExpressionForChildren();
diff --git a/src/engine/GroupBy.cpp b/src/engine/GroupBy.cpp
index cfa862170..3e8af1cb2 100644
--- a/src/engine/GroupBy.cpp
+++ b/src/engine/GroupBy.cpp
@@ -9,7 +9,7 @@
 #include <absl/strings/str_join.h>
 
 #include "engine/CallFixedSize.h"
-#include "engine/ExistsScan.h"
+#include "engine/ExistsJoin.h"
 #include "engine/IndexScan.h"
 #include "engine/Join.h"
 #include "engine/LazyGroupBy.h"
@@ -55,7 +55,7 @@ GroupBy::GroupBy(QueryExecutionContext* qec, vector<Variable> groupByVariables,
   auto sortColumns = computeSortColumns(subtree.get());
 
   for (const auto& alias : _aliases) {
-    subtree = ExistsScan::addExistsScansToSubtree(
+    subtree = ExistsJoin::addExistsScansToSubtree(
         alias._expression, std::move(subtree), getExecutionContext(),
         cancellationHandle_);
   }
diff --git a/src/util/JoinAlgorithms/FindUndefRanges.h b/src/util/JoinAlgorithms/FindUndefRanges.h
index bf15685f3..6313bea88 100644
--- a/src/util/JoinAlgorithms/FindUndefRanges.h
+++ b/src/util/JoinAlgorithms/FindUndefRanges.h
@@ -196,35 +196,4 @@ struct FindSmallerUndefRanges {
   }
 };
 constexpr FindSmallerUndefRanges findSmallerUndefRanges;
-/*
-template <std::random_access_iterator It>
-auto findSmallerUndefRanges(const auto& row, It begin, It end,
-                            bool& resultMightBeUnsorted)
-    -> cppcoro::generator<It> {
-  size_t numLastUndefined = 0;
-  assert(row.size() > 0);
-  auto it = ql::ranges::rbegin(row);
-  auto rend = ql::ranges::rend(row);
-  for (; it < rend; ++it) {
-    if (*it != Id::makeUndefined()) {
-      break;
-    }
-    ++numLastUndefined;
-  }
-
-  for (; it < rend; ++it) {
-    if (*it == Id::makeUndefined()) {
-      return findSmallerUndefRangesArbitrary(row, begin, end,
-                                             resultMightBeUnsorted);
-    }
-  }
-  if (numLastUndefined == 0) {
-    return findSmallerUndefRangesForRowsWithoutUndef(row, begin, end,
-                                                     resultMightBeUnsorted);
-  } else {
-    return findSmallerUndefRangesForRowsWithUndefInLastColumns(
-        row, numLastUndefined, begin, end, resultMightBeUnsorted);
-  }
-}
-*/
 }  // namespace ad_utility
diff --git a/test/QueryPlannerTest.cpp b/test/QueryPlannerTest.cpp
index 90462f3cc..c7d806319 100644
--- a/test/QueryPlannerTest.cpp
+++ b/test/QueryPlannerTest.cpp
@@ -2906,10 +2906,21 @@ TEST(QueryPlanner, Describe) {
 }
 
 // ____________________________________________________________________________
-TEST(QueryPlanner, GroupByRedundanteParensAndVariables) {
+TEST(QueryPlanner, GroupByRedundantParensAndVariables) {
   auto matcher = h::GroupBy({Variable{"?x"}}, {},
                             h::IndexScanFromStrings("?x", "?y", "?z"));
   h::expect("SELECT ?x { ?x ?y ?z} GROUP BY (?x)", matcher);
   h::expect("SELECT ?x { ?x ?y ?z} GROUP BY ?x ?x", matcher);
   h::expect("SELECT ?x { ?x ?y ?z} GROUP BY ?x ?x (?x)", matcher);
 }
+
+// ____________________________________________________________________________
+TEST(QueryPlanner, Exists) {
+  auto xyz = h::IndexScanFromStrings("?x", "?y", "?z");
+  auto a = h::IndexScanFromStrings("?x", "?y", "?z");
+  h::expect(
+      "SELECT * { ?x ?y ?z FILTER EXISTS {?a ?b ?c}}",
+      h::Filter("EXISTS {?a ?b ?c}",
+                h::ExistsJoin(h::IndexScanFromStrings("?x", "?y", "?z"),
+                              h::IndexScanFromStrings("?a", "?b", "?c"))));
+}
diff --git a/test/QueryPlannerTestHelpers.h b/test/QueryPlannerTestHelpers.h
index c300bf0d5..f53f30c5b 100644
--- a/test/QueryPlannerTestHelpers.h
+++ b/test/QueryPlannerTestHelpers.h
@@ -15,6 +15,7 @@
 #include "engine/CartesianProductJoin.h"
 #include "engine/CountAvailablePredicates.h"
 #include "engine/Describe.h"
+#include "engine/ExistsJoin.h"
 #include "engine/Filter.h"
 #include "engine/GroupBy.h"
 #include "engine/IndexScan.h"
@@ -405,6 +406,12 @@ inline QetMatcher Describe(
             AD_PROPERTY(::Describe, getDescribe, describeMatcher)));
 }
 
+// Match an `ExistsJoin`
+inline QetMatcher ExistsJoin(const QetMatcher& leftChild,
+                             const QetMatcher& rightChild) {
+  return RootOperation<::ExistsJoin>(AllOf(children(leftChild, rightChild)));
+}
+
 //
 inline QetMatcher QetWithWarnings(
     const std::vector<std::string>& warningSubstrings,
diff --git a/test/SparqlAntlrParserTest.cpp b/test/SparqlAntlrParserTest.cpp
index 0803f96f0..f5a65169b 100644
--- a/test/SparqlAntlrParserTest.cpp
+++ b/test/SparqlAntlrParserTest.cpp
@@ -4,6 +4,7 @@
 //          Julian Mundhahs <mundhahj@cs.uni-freiburg.de>
 //          Hannah Bast <bast@cs.uni-freiburg.de>
 
+#include <engine/sparqlExpressions/ExistsExpression.h>
 #include <gtest/gtest.h>
 
 #include <iostream>
@@ -14,6 +15,7 @@
 #include "./SparqlExpressionTestHelpers.h"
 #include "./util/GTestHelpers.h"
 #include "./util/TripleComponentTestHelpers.h"
+#include "QueryPlannerTestHelpers.h"
 #include "SparqlAntlrParserTestHelpers.h"
 #include "engine/sparqlExpressions/CountStarExpression.h"
 #include "engine/sparqlExpressions/GroupConcatExpression.h"
@@ -1860,6 +1862,43 @@ TEST(SparqlParser, binaryStringExpressions) {
   expectBuiltInCall("STRBEFORE(?x, ?y)", makeMatcher(&makeStrBeforeExpression));
 }
 
+// Matchers for EXISTS and NOT EXISTS functions.
+namespace existsTestHelpers {
+using namespace sparqlExpression;
+using namespace ::testing;
+
+// Match an EXISTS function
+auto existsMatcher(Matcher<const ParsedQuery&> pattern) {
+  return Pointee(WhenDynamicCastTo<const ExistsExpression&>(
+      AD_PROPERTY(ExistsExpression, argument, pattern)));
+}
+// Match a NOT EXISTS function
+auto notExistsMatcher(Matcher<const ParsedQuery&> pattern) {
+  return builtInCallTestHelpers::matchNaryWithChildrenMatchers(
+      &makeUnaryNegateExpression, existsMatcher(pattern));
+}
+}  // namespace existsTestHelpers
+
+// _____________________________________________________________________________
+TEST(SparqlParser, Exists) {
+  using namespace existsTestHelpers;
+  auto expectBuiltInCall = ExpectCompleteParse<&Parser::builtInCall>{};
+  // A matcher that matches the query `SELECT * { ?x <bar> ?foo}`, where the
+  // FROM and FROM NAMED clauses can still be specified via arguments.
+  using Graphs = ScanSpecificationAsTripleComponent::Graphs;
+  auto selectABarFooMatcher = [](Graphs defaultGraphs = std::nullopt,
+                                 Graphs namedGraphs = std::nullopt) {
+    return testing::AllOf(m::SelectQuery(
+        m::AsteriskSelect(),
+        m::GraphPattern(m::Triples({{Var{"?a"}, "<bar>", Var{"?foo"}}})),
+        defaultGraphs, namedGraphs));
+  };
+  expectBuiltInCall("EXISTS {?a <bar> ?foo}",
+                    existsMatcher(selectABarFooMatcher()));
+  expectBuiltInCall("NOT EXISTS {?a <bar> ?foo}",
+                    notExistsMatcher(selectABarFooMatcher()));
+}
+
 namespace aggregateTestHelpers {
 using namespace sparqlExpression;