diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg.aql
new file mode 100644
index 0000000..8c8ed73
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of avg without nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_avg.adm";
+
+let $i8 := avg([int8("1"), int8("2"), int8("3")])
+let $i16 := avg([int16("1"), int16("2"), int16("3")])
+let $i32 := avg([int32("1"), int32("2"), int32("3")])
+let $i64 := avg([int64("1"), int64("2"), int64("3")])
+let $f := avg([float("1"), float("2"), float("3")])
+let $d := avg([double("1"), double("2"), double("3")])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg_empty.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg_empty.aql
new file mode 100644
index 0000000..351f5f8
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg_empty.aql
@@ -0,0 +1,12 @@
+/*
+ * Description    : Tests the scalar version of avg with an empty list.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_avg_empty.adm";
+
+avg([ ])
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg_null.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg_null.aql
new file mode 100644
index 0000000..5108573
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_avg_null.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of avg with nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_avg_null.adm";
+
+let $i8 := avg([int8("1"), int8("2"), int8("3"), null])
+let $i16 := avg([int16("1"), int16("2"), int16("3"), null])
+let $i32 := avg([int32("1"), int32("2"), int32("3"), null])
+let $i64 := avg([int64("1"), int64("2"), int64("3"), null])
+let $f := avg([float("1"), float("2"), float("3"), null])
+let $d := avg([double("1"), double("2"), double("3"), null])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count.aql
new file mode 100644
index 0000000..3508fc6
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count.aql
@@ -0,0 +1,20 @@
+/*
+ * Description    : Tests the scalar version of count without nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_count.adm";
+
+let $i8 := count([int8("1"), int8("2"), int8("3")])
+let $i16 := count([int16("1"), int16("2"), int16("3")])
+let $i32 := count([int32("1"), int32("2"), int32("3")])
+let $i64 := count([int64("1"), int64("2"), int64("3")])
+let $f := count([float("1"), float("2"), float("3")])
+let $d := count([double("1"), double("2"), double("3")])
+let $s := count(["a", "b", "c"])
+for $i in [$i8, $i16, $i32, $i64, $f, $d, $s]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count_empty.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count_empty.aql
new file mode 100644
index 0000000..afd3dab
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count_empty.aql
@@ -0,0 +1,12 @@
+/*
+ * Description    : Tests the scalar version of count with an empty list.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_count_empty.adm";
+
+count([ ])
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count_null.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count_null.aql
new file mode 100644
index 0000000..60dd19f
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_count_null.aql
@@ -0,0 +1,20 @@
+/*
+ * Description    : Tests the scalar version of count with nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_count_null.adm";
+
+let $i8 := count([int8("1"), int8("2"), int8("3"), null])
+let $i16 := count([int16("1"), int16("2"), int16("3"), null])
+let $i32 := count([int32("1"), int32("2"), int32("3"), null])
+let $i64 := count([int64("1"), int64("2"), int64("3"), null])
+let $f := count([float("1"), float("2"), float("3"), null])
+let $d := count([double("1"), double("2"), double("3"), null])
+let $s := count(["a", "b", "c", null])
+for $i in [$i8, $i16, $i32, $i64, $f, $d, $s]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max.aql
new file mode 100644
index 0000000..1d044f8
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of max without nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_max.adm";
+
+let $i8 := max([int8("1"), int8("2"), int8("3")])
+let $i16 := max([int16("1"), int16("2"), int16("3")])
+let $i32 := max([int32("1"), int32("2"), int32("3")])
+let $i64 := max([int64("1"), int64("2"), int64("3")])
+let $f := max([float("1"), float("2"), float("3")])
+let $d := max([double("1"), double("2"), double("3")])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max_empty.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max_empty.aql
new file mode 100644
index 0000000..3a4396e
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max_empty.aql
@@ -0,0 +1,12 @@
+/*
+ * Description    : Tests the scalar version of max with an empty list.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_max_empty.adm";
+
+max([ ])
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max_null.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max_null.aql
new file mode 100644
index 0000000..7dcd368
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_max_null.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of max with nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_max_null.adm";
+
+let $i8 := max([int8("1"), int8("2"), int8("3"), null])
+let $i16 := max([int16("1"), int16("2"), int16("3"), null])
+let $i32 := max([int32("1"), int32("2"), int32("3"), null])
+let $i64 := max([int64("1"), int64("2"), int64("3"), null])
+let $f := max([float("1"), float("2"), float("3"), null])
+let $d := max([double("1"), double("2"), double("3"), null])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min.aql
new file mode 100644
index 0000000..3089758
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of min without nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_min.adm";
+
+let $i8 := min([int8("1"), int8("2"), int8("3")])
+let $i16 := min([int16("1"), int16("2"), int16("3")])
+let $i32 := min([int32("1"), int32("2"), int32("3")])
+let $i64 := min([int64("1"), int64("2"), int64("3")])
+let $f := min([float("1"), float("2"), float("3")])
+let $d := min([double("1"), double("2"), double("3")])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min_empty.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min_empty.aql
new file mode 100644
index 0000000..e242a35
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min_empty.aql
@@ -0,0 +1,12 @@
+/*
+ * Description    : Tests the scalar version of min with an empty list.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_min_empty.adm";
+
+min([ ])
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min_null.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min_null.aql
new file mode 100644
index 0000000..8601228
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_min_null.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of min with nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_min_null.adm";
+
+let $i8 := min([int8("1"), int8("2"), int8("3"), null])
+let $i16 := min([int16("1"), int16("2"), int16("3"), null])
+let $i32 := min([int32("1"), int32("2"), int32("3"), null])
+let $i64 := min([int64("1"), int64("2"), int64("3"), null])
+let $f := min([float("1"), float("2"), float("3"), null])
+let $d := min([double("1"), double("2"), double("3"), null])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum.aql
new file mode 100644
index 0000000..843360f
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of sum without nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_sum.adm";
+
+let $i8 := sum([int8("1"), int8("2"), int8("3")])
+let $i16 := sum([int16("1"), int16("2"), int16("3")])
+let $i32 := sum([int32("1"), int32("2"), int32("3")])
+let $i64 := sum([int64("1"), int64("2"), int64("3")])
+let $f := sum([float("1"), float("2"), float("3")])
+let $d := sum([double("1"), double("2"), double("3")])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum_empty.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum_empty.aql
new file mode 100644
index 0000000..35bf676
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum_empty.aql
@@ -0,0 +1,12 @@
+/*
+ * Description    : Tests the scalar version of sum with an empty list.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_sum_empty.adm";
+
+sum([ ])
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum_null.aql b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum_null.aql
new file mode 100644
index 0000000..a4c2e61
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/queries/aggregate/scalar_sum_null.aql
@@ -0,0 +1,19 @@
+/*
+ * Description    : Tests the scalar version of sum with nulls.
+ * Success        : Yes
+ */
+
+drop dataverse test if exists;
+create dataverse test;
+use dataverse test;
+
+write output to nc1:"rttest/aggregate_scalar_sum_null.adm";
+
+let $i8 := sum([int8("1"), int8("2"), int8("3"), null])
+let $i16 := sum([int16("1"), int16("2"), int16("3"), null])
+let $i32 := sum([int32("1"), int32("2"), int32("3"), null])
+let $i64 := sum([int64("1"), int64("2"), int64("3"), null])
+let $f := sum([float("1"), float("2"), float("3"), null])
+let $d := sum([double("1"), double("2"), double("3"), null])
+for $i in [$i8, $i16, $i32, $i64, $f, $d]
+return $i
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg.adm
new file mode 100644
index 0000000..483cb2f
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg.adm
@@ -0,0 +1,6 @@
+2.0
+2.0
+2.0
+2.0
+2.0
+2.0
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg_empty.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg_empty.adm
new file mode 100644
index 0000000..19765bd
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg_empty.adm
@@ -0,0 +1 @@
+null
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg_null.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg_null.adm
new file mode 100644
index 0000000..0800a91
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_avg_null.adm
@@ -0,0 +1,6 @@
+null
+null
+null
+null
+null
+null
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count.adm
new file mode 100644
index 0000000..80f0b99
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count.adm
@@ -0,0 +1,7 @@
+3
+3
+3
+3
+3
+3
+3
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count_empty.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count_empty.adm
new file mode 100644
index 0000000..573541a
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count_empty.adm
@@ -0,0 +1 @@
+0
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count_null.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count_null.adm
new file mode 100644
index 0000000..4ff1111
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_count_null.adm
@@ -0,0 +1,7 @@
+4
+4
+4
+4
+4
+4
+4
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max.adm
new file mode 100644
index 0000000..a2a1efe
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max.adm
@@ -0,0 +1,6 @@
+3i8
+3i16
+3
+3i64
+3.0f
+3.0d
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max_empty.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max_empty.adm
new file mode 100644
index 0000000..19765bd
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max_empty.adm
@@ -0,0 +1 @@
+null
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max_null.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max_null.adm
new file mode 100644
index 0000000..0800a91
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_max_null.adm
@@ -0,0 +1,6 @@
+null
+null
+null
+null
+null
+null
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min.adm
new file mode 100644
index 0000000..ebfec4e
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min.adm
@@ -0,0 +1,6 @@
+1i8
+1i16
+1
+1i64
+1.0f
+1.0d
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min_empty.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min_empty.adm
new file mode 100644
index 0000000..19765bd
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min_empty.adm
@@ -0,0 +1 @@
+null
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min_null.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min_null.adm
new file mode 100644
index 0000000..0800a91
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_min_null.adm
@@ -0,0 +1,6 @@
+null
+null
+null
+null
+null
+null
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum.adm
new file mode 100644
index 0000000..6e7617e
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum.adm
@@ -0,0 +1,6 @@
+6i8
+6i16
+6
+6i64
+6.0f
+6.0d
\ No newline at end of file
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum_empty.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum_empty.adm
new file mode 100644
index 0000000..19765bd
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum_empty.adm
@@ -0,0 +1 @@
+null
diff --git a/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum_null.adm b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum_null.adm
new file mode 100644
index 0000000..0800a91
--- /dev/null
+++ b/asterix-app/src/test/resources/runtimets/results/aggregate/scalar_sum_null.adm
@@ -0,0 +1,6 @@
+null
+null
+null
+null
+null
+null
\ No newline at end of file
diff --git a/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/AOrderedlistPrinterFactory.java b/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/AOrderedlistPrinterFactory.java
index 9edb640..563b14c 100644
--- a/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/AOrderedlistPrinterFactory.java
+++ b/asterix-om/src/main/java/edu/uci/ics/asterix/dataflow/data/nontagged/printers/AOrderedlistPrinterFactory.java
@@ -34,10 +34,6 @@
             private ATypeTag itemTag;
             private boolean typedItemList = false;
 
-            // private int itemLength;
-            // private int numberOfitems;
-            // private int itemOffset;
-
             @Override
             public void init() throws AlgebricksException {
 
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/base/SingleFieldFrameTupleReference.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/base/SingleFieldFrameTupleReference.java
index a42a3e9..c0c08fd 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/base/SingleFieldFrameTupleReference.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/base/SingleFieldFrameTupleReference.java
@@ -5,12 +5,12 @@
 
 public class SingleFieldFrameTupleReference implements IFrameTupleReference {
 
-    private byte[] fildData;
+    private byte[] fieldData;
     private int start;
     private int length;
     
-    public void reset(byte[] fildData, int start, int length) {
-        this.fildData = fildData;
+    public void reset(byte[] fieldData, int start, int length) {
+        this.fieldData = fieldData;
         this.start = start;
         this.length = length;
     }
@@ -22,7 +22,7 @@
 
     @Override
     public byte[] getFieldData(int fIdx) {
-        return fildData;
+        return fieldData;
     }
 
     @Override
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
index 17f01b9..fdf9325 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/AbstractScalarAggregateDescriptor.java
@@ -6,6 +6,7 @@
 import edu.uci.ics.asterix.om.functions.IFunctionManager;
 import edu.uci.ics.asterix.runtime.aggregates.base.AbstractAggregateFunctionDynamicDescriptor;
 import edu.uci.ics.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
+import edu.uci.ics.asterix.runtime.unnestingfunctions.std.ScanCollectionDescriptor.ScanCollectionUnnestingFunctionFactory;
 import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
 import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
 import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyAggregateFunctionFactory;
@@ -24,7 +25,8 @@
 
             @Override
             public ICopyEvaluator createEvaluator(IDataOutputProvider output) throws AlgebricksException {
-                // Always access column 0.
+                // The aggregate function will get a SingleFieldFrameTupleReference that points to the result of the ScanCollection.
+                // The list-item will always reside in the first filed (column) of the SingleFieldFrameTupleReference.
                 ICopyEvaluatorFactory[] aggFuncArgs = new ICopyEvaluatorFactory[1];
                 aggFuncArgs[0] = new ColumnAccessEvalFactory(0);
                 // Create aggregate function from this scalar version.
@@ -33,7 +35,11 @@
                 IFunctionDescriptor fd = mgr.lookupFunction(fid);
                 AbstractAggregateFunctionDynamicDescriptor aggFuncDesc = (AbstractAggregateFunctionDynamicDescriptor) fd;
                 ICopyAggregateFunctionFactory aggFuncFactory = aggFuncDesc.createAggregateFunctionFactory(aggFuncArgs);
-                return new GenericScalarAggregateFunction(args, aggFuncFactory.createAggregateFunction(output));
+                // Use ScanCollection to iterate over list items.
+                ScanCollectionUnnestingFunctionFactory scanCollectionFactory = new ScanCollectionUnnestingFunctionFactory(
+                        args[0]);
+                return new GenericScalarAggregateFunction(aggFuncFactory.createAggregateFunction(output),
+                        scanCollectionFactory);
             }
         };
     }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/GenericScalarAggregateFunction.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/GenericScalarAggregateFunction.java
index 90e62cf..0811968 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/GenericScalarAggregateFunction.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/GenericScalarAggregateFunction.java
@@ -1,65 +1,41 @@
 package edu.uci.ics.asterix.runtime.aggregates.scalar;
 
-import edu.uci.ics.asterix.common.exceptions.AsterixException;
-import edu.uci.ics.asterix.dataflow.data.nontagged.serde.AOrderedListSerializerDeserializer;
-import edu.uci.ics.asterix.om.types.ATypeTag;
-import edu.uci.ics.asterix.om.types.EnumDeserializer;
-import edu.uci.ics.asterix.om.util.NonTaggedFormatUtil;
 import edu.uci.ics.asterix.runtime.aggregates.base.SingleFieldFrameTupleReference;
 import edu.uci.ics.hyracks.algebricks.common.exceptions.AlgebricksException;
 import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyAggregateFunction;
 import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluator;
-import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyEvaluatorFactory;
+import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyUnnestingFunction;
+import edu.uci.ics.hyracks.algebricks.runtime.base.ICopyUnnestingFunctionFactory;
 import edu.uci.ics.hyracks.data.std.util.ArrayBackedValueStorage;
 import edu.uci.ics.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
 
 /**
- * Implements scalar aggregates via the corresponding
- * ICopyAggregateFunction which should be passed inside this function.
+ * Implements scalar aggregates by iterating over a collection with the ScanCollection unnesting function,
+ * and applying the corresponding ICopyAggregateFunction to each collection-item.
  */
 public class GenericScalarAggregateFunction implements ICopyEvaluator {
 
-    private final ArrayBackedValueStorage argOut = new ArrayBackedValueStorage();
-    private final ICopyEvaluator argEval;
+    private final ArrayBackedValueStorage listItemOut = new ArrayBackedValueStorage();
     private final ICopyAggregateFunction aggFunc;
+    private final ICopyUnnestingFunction scanCollection;
 
     private final SingleFieldFrameTupleReference itemTuple = new SingleFieldFrameTupleReference();
-    
-    public GenericScalarAggregateFunction(ICopyEvaluatorFactory[] args, ICopyAggregateFunction aggFunc) throws AlgebricksException {
-        this.argEval = args[0].createEvaluator(argOut);
+
+    public GenericScalarAggregateFunction(ICopyAggregateFunction aggFunc,
+            ICopyUnnestingFunctionFactory scanCollectionFactory) throws AlgebricksException {
         this.aggFunc = aggFunc;
+        this.scanCollection = scanCollectionFactory.createUnnestingFunction(listItemOut);
+        listItemOut.reset();
     }
 
     @Override
     public void evaluate(IFrameTupleReference tuple) throws AlgebricksException {
-        argOut.reset();
-        argEval.evaluate(tuple);
-        byte[] listBytes = argOut.getByteArray();
-        ATypeTag argType = EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(listBytes[0]);        
-        switch (argType) {
-            case UNORDEREDLIST: {
-                break;
-            }
-            case ORDEREDLIST: {
-                try {
-                    aggFunc.init();
-                    ATypeTag itemTag = EnumDeserializer.ATYPETAGDESERIALIZER.deserialize(listBytes[1]);
-                    int numItems = AOrderedListSerializerDeserializer.getNumberOfItems(listBytes, 0);
-                    for (int i = 0; i < numItems; i++) {
-                        int itemOffset = AOrderedListSerializerDeserializer.getItemOffset(listBytes, i);
-                        int itemLength = NonTaggedFormatUtil.getFieldValueLength(listBytes, itemOffset, itemTag, false);
-                        itemTuple.reset(listBytes, itemOffset, itemLength);
-                        aggFunc.step(itemTuple);
-                    }
-                    aggFunc.finish();
-                } catch (AsterixException e) {
-                    throw new AlgebricksException(e);
-                }
-                break;
-            }
-            default: {
-                throw new AlgebricksException("Unsupported type '" + argType + "' as input to scalar aggregate function.");
-            }
-        }        
+        scanCollection.init(tuple);
+        while (scanCollection.step()) {
+            itemTuple.reset(listItemOut.getByteArray(), 0, listItemOut.getLength());
+            aggFunc.step(itemTuple);
+            listItemOut.reset();
+        }
+        aggFunc.finish();
     }
 }
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarAvgAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarAvgAggregateDescriptor.java
new file mode 100644
index 0000000..ae2a485
--- /dev/null
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarAvgAggregateDescriptor.java
@@ -0,0 +1,22 @@
+package edu.uci.ics.asterix.runtime.aggregates.scalar;
+
+import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
+import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
+
+public class ScalarAvgAggregateDescriptor extends AbstractScalarAggregateDescriptor {
+
+    private static final long serialVersionUID = 1L;
+    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "avg", 1);
+    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
+        public IFunctionDescriptor createFunctionDescriptor() {
+            return new ScalarAvgAggregateDescriptor();
+        }
+    };
+
+    @Override
+    public FunctionIdentifier getIdentifier() {
+        return FID;
+    }
+}
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMaxAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMaxAggregateDescriptor.java
new file mode 100644
index 0000000..a71eb3c
--- /dev/null
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMaxAggregateDescriptor.java
@@ -0,0 +1,22 @@
+package edu.uci.ics.asterix.runtime.aggregates.scalar;
+
+import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
+import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
+
+public class ScalarMaxAggregateDescriptor extends AbstractScalarAggregateDescriptor {
+
+    private static final long serialVersionUID = 1L;
+    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "max", 1);
+    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
+        public IFunctionDescriptor createFunctionDescriptor() {
+            return new ScalarMaxAggregateDescriptor();
+        }
+    };
+
+    @Override
+    public FunctionIdentifier getIdentifier() {
+        return FID;
+    }
+}
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMinAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMinAggregateDescriptor.java
new file mode 100644
index 0000000..4beae60
--- /dev/null
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarMinAggregateDescriptor.java
@@ -0,0 +1,22 @@
+package edu.uci.ics.asterix.runtime.aggregates.scalar;
+
+import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
+import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
+
+public class ScalarMinAggregateDescriptor extends AbstractScalarAggregateDescriptor {
+
+    private static final long serialVersionUID = 1L;
+    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "min", 1);
+    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
+        public IFunctionDescriptor createFunctionDescriptor() {
+            return new ScalarMinAggregateDescriptor();
+        }
+    };
+
+    @Override
+    public FunctionIdentifier getIdentifier() {
+        return FID;
+    }
+}
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarSumAggregateDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarSumAggregateDescriptor.java
new file mode 100644
index 0000000..f3d9d1a
--- /dev/null
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/aggregates/scalar/ScalarSumAggregateDescriptor.java
@@ -0,0 +1,22 @@
+package edu.uci.ics.asterix.runtime.aggregates.scalar;
+
+import edu.uci.ics.asterix.common.functions.FunctionConstants;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptor;
+import edu.uci.ics.asterix.om.functions.IFunctionDescriptorFactory;
+import edu.uci.ics.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
+
+public class ScalarSumAggregateDescriptor extends AbstractScalarAggregateDescriptor {
+
+    private static final long serialVersionUID = 1L;
+    public final static FunctionIdentifier FID = new FunctionIdentifier(FunctionConstants.ASTERIX_NS, "sum", 1);
+    public static final IFunctionDescriptorFactory FACTORY = new IFunctionDescriptorFactory() {
+        public IFunctionDescriptor createFunctionDescriptor() {
+            return new ScalarSumAggregateDescriptor();
+        }
+    };
+
+    @Override
+    public FunctionIdentifier getIdentifier() {
+        return FID;
+    }
+}
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/OrderedListConstructorDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/OrderedListConstructorDescriptor.java
index 496c524..af02cdd 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/OrderedListConstructorDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/evaluators/functions/OrderedListConstructorDescriptor.java
@@ -96,7 +96,7 @@
                     try {
                         for (int i = 0; i < argEvals.length; i++) {
                             inputVal.reset();
-                            argEvals[i].evaluate(tuple);
+                            argEvals[i].evaluate(tuple);                            
                             builder.addItem(inputVal);
                         }
 
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/formats/NonTaggedDataFormat.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/formats/NonTaggedDataFormat.java
index 60e29f9..268d563 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/formats/NonTaggedDataFormat.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/formats/NonTaggedDataFormat.java
@@ -41,7 +41,11 @@
 import edu.uci.ics.asterix.om.types.AUnorderedListType;
 import edu.uci.ics.asterix.om.types.IAType;
 import edu.uci.ics.asterix.runtime.aggregates.collections.ListifyAggregateDescriptor;
+import edu.uci.ics.asterix.runtime.aggregates.scalar.ScalarAvgAggregateDescriptor;
 import edu.uci.ics.asterix.runtime.aggregates.scalar.ScalarCountAggregateDescriptor;
+import edu.uci.ics.asterix.runtime.aggregates.scalar.ScalarMaxAggregateDescriptor;
+import edu.uci.ics.asterix.runtime.aggregates.scalar.ScalarMinAggregateDescriptor;
+import edu.uci.ics.asterix.runtime.aggregates.scalar.ScalarSumAggregateDescriptor;
 import edu.uci.ics.asterix.runtime.aggregates.serializable.std.SerializableAvgAggregateDescriptor;
 import edu.uci.ics.asterix.runtime.aggregates.serializable.std.SerializableCountAggregateDescriptor;
 import edu.uci.ics.asterix.runtime.aggregates.serializable.std.SerializableGlobalAvgAggregateDescriptor;
@@ -323,6 +327,10 @@
 
         // scalar aggregates
         temp.add(ScalarCountAggregateDescriptor.FACTORY);
+        temp.add(ScalarAvgAggregateDescriptor.FACTORY);
+        temp.add(ScalarSumAggregateDescriptor.FACTORY);
+        temp.add(ScalarMaxAggregateDescriptor.FACTORY);
+        temp.add(ScalarMinAggregateDescriptor.FACTORY);
         
         // new functions - constructors
         temp.add(ABooleanConstructorDescriptor.FACTORY);
diff --git a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/unnestingfunctions/std/ScanCollectionDescriptor.java b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/unnestingfunctions/std/ScanCollectionDescriptor.java
index 7963b00..cf39008 100644
--- a/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/unnestingfunctions/std/ScanCollectionDescriptor.java
+++ b/asterix-runtime/src/main/java/edu/uci/ics/asterix/runtime/unnestingfunctions/std/ScanCollectionDescriptor.java
@@ -48,7 +48,7 @@
         return new ScanCollectionUnnestingFunctionFactory(args[0]);
     }
 
-    private static class ScanCollectionUnnestingFunctionFactory implements ICopyUnnestingFunctionFactory {
+    public static class ScanCollectionUnnestingFunctionFactory implements ICopyUnnestingFunctionFactory {
 
         private static final long serialVersionUID = 1L;