diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.1.ddl.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.1.ddl.sqlpp
new file mode 100644
index 0000000..d881c98
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.1.ddl.sqlpp
@@ -0,0 +1,48 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*
+ * Test various combinations of grouping sets
+ */
+
+drop  dataverse test if exists;
+create  dataverse test;
+
+use test;
+
+create type tenkType as closed {
+  unique1         : integer,
+  unique2         : integer,
+  two             : integer,
+  four            : integer,
+  ten             : integer,
+  twenty          : integer,
+  hundred         : integer,
+  thousand        : integer,
+  twothousand     : integer,
+  fivethous       : integer,
+  tenthous        : integer,
+  odd100          : integer,
+  even100         : integer,
+  stringu1        : string,
+  stringu2        : string,
+  string4         : string
+};
+
+create dataset tenk(tenkType) primary key unique2;
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.2.update.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.2.update.sqlpp
new file mode 100644
index 0000000..7128175
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.2.update.sqlpp
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+use test;
+
+load  dataset tenk using localfs ((`path`=`asterix_nc1://data/tenk.tbl`),(`format`=`delimited-text`),(`delimiter`=`|`));
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.3.query.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.3.query.sqlpp
new file mode 100644
index 0000000..ddd69bd
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/union/union_nested/union_nested.3.query.sqlpp
@@ -0,0 +1,93 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+use test;
+
+select two, four, ten, twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by two, four, ten, twenty
+
+union all
+select two, four, ten, twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by -two as two, -four as four, -ten as ten, -twenty as twenty
+
+union all
+select two, four, ten, twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by tostring(two) as two, tostring(four) as four, tostring(ten) as ten, tostring(twenty) as twenty
+
+union all
+select two, four, ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by two, four, ten
+
+union all
+select two, four, ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by -two as two, -four as four, -ten as ten
+
+union all
+select two, four, ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by tostring(two) as two, tostring(four) as four, tostring(ten) as ten
+
+union all
+select two, four, null as ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by two, four
+
+union all
+select two, four, null as ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by -two as two, -four as four
+
+union all
+select two, four, null as ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by tostring(two) as two, tostring(four) as four
+
+union all
+select two, null as four, null as ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by two
+
+union all
+select two, null as four, null as ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by -two as two
+
+union all
+select two, null as four, null as ten, null as twenty,
+  sum(unique1) as agg_sum
+from tenk
+group by tostring(two) as two
+
+order by two, four, ten, twenty;
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/results/union/union_nested/union_nested.3.adm b/asterixdb/asterix-app/src/test/resources/runtimets/results/union/union_nested/union_nested.3.adm
new file mode 100644
index 0000000..4737f9e
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/results/union/union_nested/union_nested.3.adm
@@ -0,0 +1,138 @@
+{ "agg_sum": 25000000, "two": -1, "four": null, "ten": null, "twenty": null }
+{ "agg_sum": 12502500, "two": -1, "four": -3, "ten": null, "twenty": null }
+{ "agg_sum": 2504500, "two": -1, "four": -3, "ten": -9, "twenty": null }
+{ "agg_sum": 2504500, "two": -1, "four": -3, "ten": -9, "twenty": -19 }
+{ "agg_sum": 2498500, "two": -1, "four": -3, "ten": -7, "twenty": null }
+{ "agg_sum": 2498500, "two": -1, "four": -3, "ten": -7, "twenty": -7 }
+{ "agg_sum": 2502500, "two": -1, "four": -3, "ten": -5, "twenty": null }
+{ "agg_sum": 2502500, "two": -1, "four": -3, "ten": -5, "twenty": -15 }
+{ "agg_sum": 2496500, "two": -1, "four": -3, "ten": -3, "twenty": null }
+{ "agg_sum": 2496500, "two": -1, "four": -3, "ten": -3, "twenty": -3 }
+{ "agg_sum": 2500500, "two": -1, "four": -3, "ten": -1, "twenty": null }
+{ "agg_sum": 2500500, "two": -1, "four": -3, "ten": -1, "twenty": -11 }
+{ "agg_sum": 12497500, "two": -1, "four": -1, "ten": null, "twenty": null }
+{ "agg_sum": 2499500, "two": -1, "four": -1, "ten": -9, "twenty": null }
+{ "agg_sum": 2499500, "two": -1, "four": -1, "ten": -9, "twenty": -9 }
+{ "agg_sum": 2503500, "two": -1, "four": -1, "ten": -7, "twenty": null }
+{ "agg_sum": 2503500, "two": -1, "four": -1, "ten": -7, "twenty": -17 }
+{ "agg_sum": 2497500, "two": -1, "four": -1, "ten": -5, "twenty": null }
+{ "agg_sum": 2497500, "two": -1, "four": -1, "ten": -5, "twenty": -5 }
+{ "agg_sum": 2501500, "two": -1, "four": -1, "ten": -3, "twenty": null }
+{ "agg_sum": 2501500, "two": -1, "four": -1, "ten": -3, "twenty": -13 }
+{ "agg_sum": 2495500, "two": -1, "four": -1, "ten": -1, "twenty": null }
+{ "agg_sum": 2495500, "two": -1, "four": -1, "ten": -1, "twenty": -1 }
+{ "agg_sum": 24995000, "two": 0, "four": null, "ten": null, "twenty": null }
+{ "agg_sum": 24995000, "two": 0, "four": null, "ten": null, "twenty": null }
+{ "agg_sum": 12500000, "two": 0, "four": -2, "ten": null, "twenty": null }
+{ "agg_sum": 2504000, "two": 0, "four": -2, "ten": -8, "twenty": null }
+{ "agg_sum": 2504000, "two": 0, "four": -2, "ten": -8, "twenty": -18 }
+{ "agg_sum": 2498000, "two": 0, "four": -2, "ten": -6, "twenty": null }
+{ "agg_sum": 2498000, "two": 0, "four": -2, "ten": -6, "twenty": -6 }
+{ "agg_sum": 2502000, "two": 0, "four": -2, "ten": -4, "twenty": null }
+{ "agg_sum": 2502000, "two": 0, "four": -2, "ten": -4, "twenty": -14 }
+{ "agg_sum": 2496000, "two": 0, "four": -2, "ten": -2, "twenty": null }
+{ "agg_sum": 2496000, "two": 0, "four": -2, "ten": -2, "twenty": -2 }
+{ "agg_sum": 2500000, "two": 0, "four": -2, "ten": 0, "twenty": null }
+{ "agg_sum": 2500000, "two": 0, "four": -2, "ten": 0, "twenty": -10 }
+{ "agg_sum": 12495000, "two": 0, "four": 0, "ten": null, "twenty": null }
+{ "agg_sum": 12495000, "two": 0, "four": 0, "ten": null, "twenty": null }
+{ "agg_sum": 2499000, "two": 0, "four": 0, "ten": -8, "twenty": null }
+{ "agg_sum": 2499000, "two": 0, "four": 0, "ten": -8, "twenty": -8 }
+{ "agg_sum": 2503000, "two": 0, "four": 0, "ten": -6, "twenty": null }
+{ "agg_sum": 2503000, "two": 0, "four": 0, "ten": -6, "twenty": -16 }
+{ "agg_sum": 2497000, "two": 0, "four": 0, "ten": -4, "twenty": null }
+{ "agg_sum": 2497000, "two": 0, "four": 0, "ten": -4, "twenty": -4 }
+{ "agg_sum": 2501000, "two": 0, "four": 0, "ten": -2, "twenty": null }
+{ "agg_sum": 2501000, "two": 0, "four": 0, "ten": -2, "twenty": -12 }
+{ "agg_sum": 2495000, "two": 0, "four": 0, "ten": 0, "twenty": null }
+{ "agg_sum": 2495000, "two": 0, "four": 0, "ten": 0, "twenty": null }
+{ "agg_sum": 2495000, "two": 0, "four": 0, "ten": 0, "twenty": 0 }
+{ "agg_sum": 2495000, "two": 0, "four": 0, "ten": 0, "twenty": 0 }
+{ "agg_sum": 2501000, "two": 0, "four": 0, "ten": 2, "twenty": null }
+{ "agg_sum": 2501000, "two": 0, "four": 0, "ten": 2, "twenty": 12 }
+{ "agg_sum": 2497000, "two": 0, "four": 0, "ten": 4, "twenty": null }
+{ "agg_sum": 2497000, "two": 0, "four": 0, "ten": 4, "twenty": 4 }
+{ "agg_sum": 2503000, "two": 0, "four": 0, "ten": 6, "twenty": null }
+{ "agg_sum": 2503000, "two": 0, "four": 0, "ten": 6, "twenty": 16 }
+{ "agg_sum": 2499000, "two": 0, "four": 0, "ten": 8, "twenty": null }
+{ "agg_sum": 2499000, "two": 0, "four": 0, "ten": 8, "twenty": 8 }
+{ "agg_sum": 12500000, "two": 0, "four": 2, "ten": null, "twenty": null }
+{ "agg_sum": 2500000, "two": 0, "four": 2, "ten": 0, "twenty": null }
+{ "agg_sum": 2500000, "two": 0, "four": 2, "ten": 0, "twenty": 10 }
+{ "agg_sum": 2496000, "two": 0, "four": 2, "ten": 2, "twenty": null }
+{ "agg_sum": 2496000, "two": 0, "four": 2, "ten": 2, "twenty": 2 }
+{ "agg_sum": 2502000, "two": 0, "four": 2, "ten": 4, "twenty": null }
+{ "agg_sum": 2502000, "two": 0, "four": 2, "ten": 4, "twenty": 14 }
+{ "agg_sum": 2498000, "two": 0, "four": 2, "ten": 6, "twenty": null }
+{ "agg_sum": 2498000, "two": 0, "four": 2, "ten": 6, "twenty": 6 }
+{ "agg_sum": 2504000, "two": 0, "four": 2, "ten": 8, "twenty": null }
+{ "agg_sum": 2504000, "two": 0, "four": 2, "ten": 8, "twenty": 18 }
+{ "agg_sum": 25000000, "two": 1, "four": null, "ten": null, "twenty": null }
+{ "agg_sum": 12497500, "two": 1, "four": 1, "ten": null, "twenty": null }
+{ "agg_sum": 2495500, "two": 1, "four": 1, "ten": 1, "twenty": null }
+{ "agg_sum": 2495500, "two": 1, "four": 1, "ten": 1, "twenty": 1 }
+{ "agg_sum": 2501500, "two": 1, "four": 1, "ten": 3, "twenty": null }
+{ "agg_sum": 2501500, "two": 1, "four": 1, "ten": 3, "twenty": 13 }
+{ "agg_sum": 2497500, "two": 1, "four": 1, "ten": 5, "twenty": null }
+{ "agg_sum": 2497500, "two": 1, "four": 1, "ten": 5, "twenty": 5 }
+{ "agg_sum": 2503500, "two": 1, "four": 1, "ten": 7, "twenty": null }
+{ "agg_sum": 2503500, "two": 1, "four": 1, "ten": 7, "twenty": 17 }
+{ "agg_sum": 2499500, "two": 1, "four": 1, "ten": 9, "twenty": null }
+{ "agg_sum": 2499500, "two": 1, "four": 1, "ten": 9, "twenty": 9 }
+{ "agg_sum": 12502500, "two": 1, "four": 3, "ten": null, "twenty": null }
+{ "agg_sum": 2500500, "two": 1, "four": 3, "ten": 1, "twenty": null }
+{ "agg_sum": 2500500, "two": 1, "four": 3, "ten": 1, "twenty": 11 }
+{ "agg_sum": 2496500, "two": 1, "four": 3, "ten": 3, "twenty": null }
+{ "agg_sum": 2496500, "two": 1, "four": 3, "ten": 3, "twenty": 3 }
+{ "agg_sum": 2502500, "two": 1, "four": 3, "ten": 5, "twenty": null }
+{ "agg_sum": 2502500, "two": 1, "four": 3, "ten": 5, "twenty": 15 }
+{ "agg_sum": 2498500, "two": 1, "four": 3, "ten": 7, "twenty": null }
+{ "agg_sum": 2498500, "two": 1, "four": 3, "ten": 7, "twenty": 7 }
+{ "agg_sum": 2504500, "two": 1, "four": 3, "ten": 9, "twenty": null }
+{ "agg_sum": 2504500, "two": 1, "four": 3, "ten": 9, "twenty": 19 }
+{ "agg_sum": 24995000, "two": "0", "four": null, "ten": null, "twenty": null }
+{ "agg_sum": 12495000, "two": "0", "four": "0", "ten": null, "twenty": null }
+{ "agg_sum": 2495000, "two": "0", "four": "0", "ten": "0", "twenty": null }
+{ "agg_sum": 2495000, "two": "0", "four": "0", "ten": "0", "twenty": "0" }
+{ "agg_sum": 2501000, "two": "0", "four": "0", "ten": "2", "twenty": null }
+{ "agg_sum": 2501000, "two": "0", "four": "0", "ten": "2", "twenty": "12" }
+{ "agg_sum": 2497000, "two": "0", "four": "0", "ten": "4", "twenty": null }
+{ "agg_sum": 2497000, "two": "0", "four": "0", "ten": "4", "twenty": "4" }
+{ "agg_sum": 2503000, "two": "0", "four": "0", "ten": "6", "twenty": null }
+{ "agg_sum": 2503000, "two": "0", "four": "0", "ten": "6", "twenty": "16" }
+{ "agg_sum": 2499000, "two": "0", "four": "0", "ten": "8", "twenty": null }
+{ "agg_sum": 2499000, "two": "0", "four": "0", "ten": "8", "twenty": "8" }
+{ "agg_sum": 12500000, "two": "0", "four": "2", "ten": null, "twenty": null }
+{ "agg_sum": 2500000, "two": "0", "four": "2", "ten": "0", "twenty": null }
+{ "agg_sum": 2500000, "two": "0", "four": "2", "ten": "0", "twenty": "10" }
+{ "agg_sum": 2496000, "two": "0", "four": "2", "ten": "2", "twenty": null }
+{ "agg_sum": 2496000, "two": "0", "four": "2", "ten": "2", "twenty": "2" }
+{ "agg_sum": 2502000, "two": "0", "four": "2", "ten": "4", "twenty": null }
+{ "agg_sum": 2502000, "two": "0", "four": "2", "ten": "4", "twenty": "14" }
+{ "agg_sum": 2498000, "two": "0", "four": "2", "ten": "6", "twenty": null }
+{ "agg_sum": 2498000, "two": "0", "four": "2", "ten": "6", "twenty": "6" }
+{ "agg_sum": 2504000, "two": "0", "four": "2", "ten": "8", "twenty": null }
+{ "agg_sum": 2504000, "two": "0", "four": "2", "ten": "8", "twenty": "18" }
+{ "agg_sum": 25000000, "two": "1", "four": null, "ten": null, "twenty": null }
+{ "agg_sum": 12497500, "two": "1", "four": "1", "ten": null, "twenty": null }
+{ "agg_sum": 2495500, "two": "1", "four": "1", "ten": "1", "twenty": null }
+{ "agg_sum": 2495500, "two": "1", "four": "1", "ten": "1", "twenty": "1" }
+{ "agg_sum": 2501500, "two": "1", "four": "1", "ten": "3", "twenty": null }
+{ "agg_sum": 2501500, "two": "1", "four": "1", "ten": "3", "twenty": "13" }
+{ "agg_sum": 2497500, "two": "1", "four": "1", "ten": "5", "twenty": null }
+{ "agg_sum": 2497500, "two": "1", "four": "1", "ten": "5", "twenty": "5" }
+{ "agg_sum": 2503500, "two": "1", "four": "1", "ten": "7", "twenty": null }
+{ "agg_sum": 2503500, "two": "1", "four": "1", "ten": "7", "twenty": "17" }
+{ "agg_sum": 2499500, "two": "1", "four": "1", "ten": "9", "twenty": null }
+{ "agg_sum": 2499500, "two": "1", "four": "1", "ten": "9", "twenty": "9" }
+{ "agg_sum": 12502500, "two": "1", "four": "3", "ten": null, "twenty": null }
+{ "agg_sum": 2500500, "two": "1", "four": "3", "ten": "1", "twenty": null }
+{ "agg_sum": 2500500, "two": "1", "four": "3", "ten": "1", "twenty": "11" }
+{ "agg_sum": 2496500, "two": "1", "four": "3", "ten": "3", "twenty": null }
+{ "agg_sum": 2496500, "two": "1", "four": "3", "ten": "3", "twenty": "3" }
+{ "agg_sum": 2502500, "two": "1", "four": "3", "ten": "5", "twenty": null }
+{ "agg_sum": 2502500, "two": "1", "four": "3", "ten": "5", "twenty": "15" }
+{ "agg_sum": 2498500, "two": "1", "four": "3", "ten": "7", "twenty": null }
+{ "agg_sum": 2498500, "two": "1", "four": "3", "ten": "7", "twenty": "7" }
+{ "agg_sum": 2504500, "two": "1", "four": "3", "ten": "9", "twenty": null }
+{ "agg_sum": 2504500, "two": "1", "four": "3", "ten": "9", "twenty": "19" }
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml b/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
index a578690..8fbff50 100644
--- a/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
@@ -12349,6 +12349,11 @@
       </compilation-unit>
     </test-case>
     <test-case FilePath="union">
+      <compilation-unit name="union_nested">
+        <output-dir compare="Text">union_nested</output-dir>
+      </compilation-unit>
+    </test-case>
+    <test-case FilePath="union">
       <compilation-unit name="union_orderby">
         <output-dir compare="Text">union_orderby</output-dir>
       </compilation-unit>
diff --git a/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/logical/UnionAllOperator.java b/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/logical/UnionAllOperator.java
index 9defb4f2..d394e2f 100644
--- a/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/logical/UnionAllOperator.java
+++ b/hyracks-fullstack/algebricks/algebricks-core/src/main/java/org/apache/hyracks/algebricks/core/algebra/operators/logical/UnionAllOperator.java
@@ -19,6 +19,7 @@
 package org.apache.hyracks.algebricks.core.algebra.operators.logical;
 
 import java.util.ArrayList;
+import java.util.LinkedHashSet;
 import java.util.List;
 
 import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
@@ -77,25 +78,34 @@
 
     @Override
     public void recomputeSchema() {
-        schema = new ArrayList<LogicalVariable>();
-        for (LogicalVariable v1 : inputs.get(0).getValue().getSchema()) {
-            for (Triple<LogicalVariable, LogicalVariable, LogicalVariable> t : varMap) {
-                if (t.first.equals(v1)) {
-                    schema.add(t.third);
-                } else {
-                    schema.add(v1);
-                }
+        LinkedHashSet<LogicalVariable> outVarSet = new LinkedHashSet<>();
+        for (int i = 0, ln = inputs.size(); i < ln; i++) {
+            for (LogicalVariable inVar : inputs.get(i).getValue().getSchema()) {
+                LogicalVariable outVar = findOutputVar(inVar, i);
+                outVarSet.add(outVar != null ? outVar : inVar);
             }
         }
-        for (LogicalVariable v2 : inputs.get(1).getValue().getSchema()) {
-            for (Triple<LogicalVariable, LogicalVariable, LogicalVariable> t : varMap) {
-                if (t.second.equals(v2)) {
-                    schema.add(t.third);
-                } else {
-                    schema.add(v2);
-                }
+        schema = new ArrayList<>(outVarSet);
+    }
+
+    private LogicalVariable findOutputVar(LogicalVariable inputVar, int inputIdx) {
+        for (Triple<LogicalVariable, LogicalVariable, LogicalVariable> t : varMap) {
+            LogicalVariable testVar;
+            switch (inputIdx) {
+                case 0:
+                    testVar = t.first;
+                    break;
+                case 1:
+                    testVar = t.second;
+                    break;
+                default:
+                    throw new IllegalArgumentException(String.valueOf(inputIdx));
+            }
+            if (inputVar.equals(testVar)) {
+                return t.third;
             }
         }
+        return null;
     }
 
     @Override