diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.1.ddl.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.1.ddl.sqlpp
new file mode 100644
index 0000000..b09662f
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.1.ddl.sqlpp
@@ -0,0 +1,28 @@
+/*
+ * 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.
+ */
+/*
+ * Description  : Run avg over a list of mixed types (ASTERIXDB-3015)
+ */
+
+drop  dataverse test if exists;
+create  dataverse test;
+
+use test;
+
+create dataset d1(id bigint) open type primary key id;
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.2.update.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.2.update.sqlpp
new file mode 100644
index 0000000..a5943c9
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.2.update.sqlpp
@@ -0,0 +1,30 @@
+/*
+ * 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.
+ */
+/*
+ * Description  : Run avg over a list of mixed types (ASTERIXDB-3015)
+ */
+
+use test;
+
+insert into d1 (
+  [
+    { "id": 1, "i": 1, "v": [ "a", 1, 2, 3 ] },
+    { "id": 2, "i": 2, "v": [ "b", 4, 5, 6 ] }
+  ]
+);
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.3.query.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.3.query.sqlpp
new file mode 100644
index 0000000..eff95e0
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.3.query.sqlpp
@@ -0,0 +1,26 @@
+/*
+ * 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.
+ */
+/*
+* Description  : Run avg over a list of mixed types (ASTERIXDB-3015)
+* Expected Res : Failure
+*/
+
+-- param max-warnings:json=100
+
+select avg(x) a from ["a", 1, 2, 3] x;
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.4.query.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.4.query.sqlpp
new file mode 100644
index 0000000..756194b
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.4.query.sqlpp
@@ -0,0 +1,31 @@
+/*
+ * 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.
+ */
+/*
+* Description  : Run avg over a list of mixed types (ASTERIXDB-3015)
+* Expected Res : Failure
+*/
+
+-- param max-warnings:json=100
+
+use test;
+
+select d1.id, avg(v) a
+from d1, d1.v
+group by d1.id
+order by d1.id;
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.5.query.sqlpp b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.5.query.sqlpp
new file mode 100644
index 0000000..71b22e7
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/queries_sqlpp/aggregate-sql-sugar/avg_mixed/avg_mixed.5.query.sqlpp
@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+/*
+* Description  : Run avg over a list of mixed types (ASTERIXDB-3015)
+* Expected Res : Failure
+*/
+
+-- param max-warnings:json=100
+
+use test;
+
+
+select d1.id, avg(v) a
+from d1, d1.v
+/* +hash */ group by d1.id
+order by d1.id;
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.3.adm b/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.3.adm
new file mode 100644
index 0000000..53bdaa0
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.3.adm
@@ -0,0 +1 @@
+{ "a": 2.0 }
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.4.adm b/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.4.adm
new file mode 100644
index 0000000..35fa557
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.4.adm
@@ -0,0 +1,2 @@
+{ "id": 1, "a": 2.0 }
+{ "id": 2, "a": 5.0 }
\ No newline at end of file
diff --git a/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.5.adm b/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.5.adm
new file mode 100644
index 0000000..35fa557
--- /dev/null
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/results/aggregate-sql-sugar/avg_mixed/avg_mixed.5.adm
@@ -0,0 +1,2 @@
+{ "id": 1, "a": 2.0 }
+{ "id": 2, "a": 5.0 }
\ No newline at end of file
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 bc9353b..8b6b7c0 100644
--- a/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
+++ b/asterixdb/asterix-app/src/test/resources/runtimets/testsuite_sqlpp.xml
@@ -2883,6 +2883,14 @@
         <expected-error>ASX1079: Compilation error: arrayagg is a SQL-92 aggregate function. The SQL++ core aggregate function strict_arrayagg could potentially express the intent.</expected-error>
       </compilation-unit>
     </test-case>
+    <test-case FilePath="aggregate-sql-sugar" check-warnings="true">
+      <compilation-unit name="avg_mixed">
+        <output-dir compare="Text">avg_mixed</output-dir>
+        <expected-warn>ASX0004: Unsupported type: agg-avg cannot process input type string (in line 26, at column 12)</expected-warn>
+        <expected-warn>ASX0004: Unsupported type: agg-avg cannot process input type string (in line 28, at column 19)</expected-warn>
+        <expected-warn>ASX0004: Unsupported type: agg-avg cannot process input type string (in line 29, at column 19)</expected-warn>
+      </compilation-unit>
+    </test-case>
     <test-case FilePath="aggregate-sql-sugar">
       <compilation-unit name="distinct_mixed">
         <output-dir compare="Text">distinct_mixed</output-dir>
diff --git a/asterixdb/asterix-runtime/src/main/java/org/apache/asterix/runtime/aggregates/std/AbstractAvgAggregateFunction.java b/asterixdb/asterix-runtime/src/main/java/org/apache/asterix/runtime/aggregates/std/AbstractAvgAggregateFunction.java
index d2367f9..fc668d2 100644
--- a/asterixdb/asterix-runtime/src/main/java/org/apache/asterix/runtime/aggregates/std/AbstractAvgAggregateFunction.java
+++ b/asterixdb/asterix-runtime/src/main/java/org/apache/asterix/runtime/aggregates/std/AbstractAvgAggregateFunction.java
@@ -136,12 +136,13 @@
         int offset = inputVal.getStartOffset();
 
         ATypeTag typeTag = EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(data[offset]);
+        ATypeTag aggTypeTag = aggType;
         if (typeTag == ATypeTag.MISSING || typeTag == ATypeTag.NULL) {
             processNull();
             return;
-        } else if (aggType == ATypeTag.SYSTEM_NULL) {
-            aggType = typeTag;
-        } else if (typeTag != ATypeTag.SYSTEM_NULL && !ATypeHierarchy.isCompatible(typeTag, aggType)) {
+        } else if (aggTypeTag == ATypeTag.SYSTEM_NULL) {
+            aggTypeTag = typeTag;
+        } else if (typeTag != ATypeTag.SYSTEM_NULL && !ATypeHierarchy.isCompatible(typeTag, aggTypeTag)) {
             // Issue warning only once and treat current tuple as null
             if (!isWarned) {
                 isWarned = true;
@@ -149,8 +150,8 @@
             }
             processNull();
             return;
-        } else if (ATypeHierarchy.canPromote(aggType, typeTag)) {
-            aggType = typeTag;
+        } else if (ATypeHierarchy.canPromote(aggTypeTag, typeTag)) {
+            aggTypeTag = typeTag;
         }
 
         switch (typeTag) {
@@ -195,6 +196,7 @@
             }
         }
         count++;
+        aggType = aggTypeTag;
     }
 
     protected void finishPartialResults(IPointable result) throws HyracksDataException {