diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java
index 892a4ea..e842b7b 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinEnum.java
@@ -300,14 +300,15 @@
         ScalarFunctionCallExpression andExpr = new ScalarFunctionCallExpression(
                 BuiltinFunctions.getBuiltinFunctionInfo(AlgebricksBuiltinFunctions.AND));
 
-        // at least one equality predicate needs to be present for a hash join to be possible.
+        // All the join predicates need to be equality predicates for a hash join to be possible.
         boolean eqPredFound = false;
         for (int joinNum : newJoinConditions) {
             // need to AND all the expressions.
             JoinCondition jc = joinConditions.get(joinNum);
-            if (jc.comparisonType == JoinCondition.comparisonOp.OP_EQ) {
-                eqPredFound = true;
+            if (jc.comparisonType != JoinCondition.comparisonOp.OP_EQ) {
+                return null;
             }
+            eqPredFound = true;
             andExpr.getArguments().add(new MutableObject<>(jc.joinCondition));
         }
         // return null if no equality predicates were found
diff --git a/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/ch2/ch2_q7.plan b/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/ch2/ch2_q7.plan
index a6eab49..1ae72b1 100644
--- a/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/ch2/ch2_q7.plan
+++ b/asterixdb/asterix-app/src/test/resources/optimizerts/results_cbo/ch2/ch2_q7.plan
@@ -18,87 +18,85 @@
                   -- STREAM_PROJECT  |PARTITIONED|
                     -- ASSIGN  |PARTITIONED|
                       -- STREAM_PROJECT  |PARTITIONED|
-                        -- STREAM_SELECT  |PARTITIONED|
-                          -- STREAM_PROJECT  |PARTITIONED|
+                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                          -- HYBRID_HASH_JOIN [$$303, $$326][$$277, $$300]  |PARTITIONED|
                             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                              -- HYBRID_HASH_JOIN [$$288][$$304]  |PARTITIONED|
-                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                              -- STREAM_PROJECT  |PARTITIONED|
+                                -- ASSIGN  |PARTITIONED|
                                   -- STREAM_PROJECT  |PARTITIONED|
                                     -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                      -- HYBRID_HASH_JOIN [$$277][$$303]  |PARTITIONED|
-                                        -- HASH_PARTITION_EXCHANGE [$$277]  |PARTITIONED|
+                                      -- NESTED_LOOP  |PARTITIONED|
+                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                                           -- STREAM_PROJECT  |PARTITIONED|
                                             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                              -- HYBRID_HASH_JOIN [$$300][$$326]  |PARTITIONED|
+                                              -- HYBRID_HASH_JOIN [$$304][$$288]  |PARTITIONED|
                                                 -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                  -- STREAM_PROJECT  |PARTITIONED|
-                                                    -- ASSIGN  |PARTITIONED|
+                                                  -- REPLICATE  |PARTITIONED|
+                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
                                                       -- STREAM_PROJECT  |PARTITIONED|
-                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- DATASOURCE_SCAN (test.supplier)  |PARTITIONED|
+                                                        -- ASSIGN  |PARTITIONED|
+                                                          -- STREAM_PROJECT  |PARTITIONED|
                                                             -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                              -- DATASOURCE_SCAN (test.nation)  |PARTITIONED|
+                                                                -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                                  -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
                                                 -- BROADCAST_EXCHANGE  |PARTITIONED|
                                                   -- STREAM_PROJECT  |PARTITIONED|
-                                                    -- ASSIGN  |PARTITIONED|
-                                                      -- STREAM_PROJECT  |PARTITIONED|
+                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                      -- HYBRID_HASH_JOIN [$$275, $$276][$$310, $$311]  |PARTITIONED|
                                                         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- HYBRID_HASH_JOIN [$$275, $$276][$$310, $$311]  |PARTITIONED|
-                                                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                              -- STREAM_PROJECT  |PARTITIONED|
-                                                                -- ASSIGN  |PARTITIONED|
-                                                                  -- STREAM_PROJECT  |PARTITIONED|
-                                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                                      -- DATASOURCE_SCAN (test.stock)  |PARTITIONED|
-                                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
-                                                            -- BROADCAST_EXCHANGE  |PARTITIONED|
+                                                          -- STREAM_PROJECT  |PARTITIONED|
+                                                            -- ASSIGN  |PARTITIONED|
                                                               -- STREAM_PROJECT  |PARTITIONED|
                                                                 -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                                  -- HYBRID_HASH_JOIN [$$291, $$293, $$295][$$305, $$306, $$307]  |PARTITIONED|
-                                                                    -- HASH_PARTITION_EXCHANGE [$$291, $$293, $$295]  |PARTITIONED|
+                                                                  -- DATASOURCE_SCAN (test.stock)  |PARTITIONED|
+                                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                                      -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                        -- BROADCAST_EXCHANGE  |PARTITIONED|
+                                                          -- STREAM_PROJECT  |PARTITIONED|
+                                                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                              -- HYBRID_HASH_JOIN [$$291, $$293, $$295][$$305, $$306, $$307]  |PARTITIONED|
+                                                                -- HASH_PARTITION_EXCHANGE [$$291, $$293, $$295]  |PARTITIONED|
+                                                                  -- STREAM_PROJECT  |PARTITIONED|
+                                                                    -- STREAM_SELECT  |PARTITIONED|
                                                                       -- STREAM_PROJECT  |PARTITIONED|
-                                                                        -- STREAM_SELECT  |PARTITIONED|
+                                                                        -- ASSIGN  |PARTITIONED|
                                                                           -- STREAM_PROJECT  |PARTITIONED|
-                                                                            -- ASSIGN  |PARTITIONED|
+                                                                            -- UNNEST  |PARTITIONED|
                                                                               -- STREAM_PROJECT  |PARTITIONED|
-                                                                                -- UNNEST  |PARTITIONED|
+                                                                                -- ASSIGN  |PARTITIONED|
                                                                                   -- STREAM_PROJECT  |PARTITIONED|
-                                                                                    -- ASSIGN  |PARTITIONED|
-                                                                                      -- STREAM_PROJECT  |PARTITIONED|
+                                                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                                                      -- DATASOURCE_SCAN (test.orders)  |PARTITIONED|
                                                                                         -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                                                          -- DATASOURCE_SCAN (test.orders)  |PARTITIONED|
-                                                                                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                                                              -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
-                                                                    -- HASH_PARTITION_EXCHANGE [$$305, $$306, $$307]  |PARTITIONED|
+                                                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                                -- HASH_PARTITION_EXCHANGE [$$305, $$306, $$307]  |PARTITIONED|
+                                                                  -- ASSIGN  |PARTITIONED|
+                                                                    -- STREAM_PROJECT  |PARTITIONED|
                                                                       -- ASSIGN  |PARTITIONED|
                                                                         -- STREAM_PROJECT  |PARTITIONED|
-                                                                          -- ASSIGN  |PARTITIONED|
-                                                                            -- STREAM_PROJECT  |PARTITIONED|
+                                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                                            -- DATASOURCE_SCAN (test.customer)  |PARTITIONED|
                                                                               -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                                                -- DATASOURCE_SCAN (test.customer)  |PARTITIONED|
-                                                                                  -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                                                    -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
-                                        -- HASH_PARTITION_EXCHANGE [$$303]  |PARTITIONED|
-                                          -- REPLICATE  |PARTITIONED|
-                                            -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                              -- STREAM_PROJECT  |PARTITIONED|
-                                                -- ASSIGN  |PARTITIONED|
-                                                  -- STREAM_PROJECT  |PARTITIONED|
-                                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                      -- DATASOURCE_SCAN (test.nation)  |PARTITIONED|
-                                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
-                                -- BROADCAST_EXCHANGE  |PARTITIONED|
-                                  -- STREAM_PROJECT  |PARTITIONED|
-                                    -- ASSIGN  |PARTITIONED|
-                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                        -- REPLICATE  |PARTITIONED|
-                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                            -- STREAM_PROJECT  |PARTITIONED|
-                                              -- ASSIGN  |PARTITIONED|
-                                                -- STREAM_PROJECT  |PARTITIONED|
+                                                                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                        -- BROADCAST_EXCHANGE  |PARTITIONED|
+                                          -- STREAM_PROJECT  |PARTITIONED|
+                                            -- ASSIGN  |PARTITIONED|
+                                              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                -- REPLICATE  |PARTITIONED|
                                                   -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                    -- DATASOURCE_SCAN (test.nation)  |PARTITIONED|
-                                                      -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
-                                                        -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                                                    -- STREAM_PROJECT  |PARTITIONED|
+                                                      -- ASSIGN  |PARTITIONED|
+                                                        -- STREAM_PROJECT  |PARTITIONED|
+                                                          -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                            -- DATASOURCE_SCAN (test.nation)  |PARTITIONED|
+                                                              -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                                                -- EMPTY_TUPLE_SOURCE  |PARTITIONED|
+                            -- BROADCAST_EXCHANGE  |PARTITIONED|
+                              -- STREAM_PROJECT  |PARTITIONED|
+                                -- ASSIGN  |PARTITIONED|
+                                  -- STREAM_PROJECT  |PARTITIONED|
+                                    -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                      -- DATASOURCE_SCAN (test.supplier)  |PARTITIONED|
+                                        -- ONE_TO_ONE_EXCHANGE  |PARTITIONED|
+                                          -- EMPTY_TUPLE_SOURCE  |PARTITIONED|