diff --git a/src/core/etl/src/Flow/ETL/Function/Round.php b/src/core/etl/src/Flow/ETL/Function/Round.php
index ef49e271e..5ae982038 100644
--- a/src/core/etl/src/Flow/ETL/Function/Round.php
+++ b/src/core/etl/src/Flow/ETL/Function/Round.php
@@ -15,7 +15,7 @@ public function __construct(
     ) {
     }
 
-    public function eval(Row $row) : ?float
+    public function eval(Row $row) : int|float|null
     {
         $value = (new Parameter($this->value))->asNumber($row);
         $precision = (new Parameter($this->precision))->asInt($row);
@@ -29,6 +29,6 @@ public function eval(Row $row) : ?float
             $mode = 1;
         }
 
-        return \round($value, $precision, $mode);
+        return $precision === 0 ? (int) \round($value, $precision, $mode) : \round($value, $precision, $mode);
     }
 }
diff --git a/src/core/etl/tests/Flow/ETL/Tests/Integration/DataFrame/GroupByTest.php b/src/core/etl/tests/Flow/ETL/Tests/Integration/DataFrame/GroupByTest.php
index 19dbe14a4..1e42bd585 100644
--- a/src/core/etl/tests/Flow/ETL/Tests/Integration/DataFrame/GroupByTest.php
+++ b/src/core/etl/tests/Flow/ETL/Tests/Integration/DataFrame/GroupByTest.php
@@ -464,9 +464,9 @@ public function test_window_avg_function() : void
 
         self::assertSame(
             [
-                ['department' => 'Sales', 'avg_salary' => 3917.0],
-                ['department' => 'Marketing', 'avg_salary' => 2940.0],
-                ['department' => 'Finance', 'avg_salary' => 3550.0],
+                ['department' => 'Sales', 'avg_salary' => 3917],
+                ['department' => 'Marketing', 'avg_salary' => 2940],
+                ['department' => 'Finance', 'avg_salary' => 3550],
             ],
             df()
                 ->from(from_all(from_memory($memoryPage1), from_memory($memoryPage2)))
diff --git a/src/core/etl/tests/Flow/ETL/Tests/Unit/Function/RoundTest.php b/src/core/etl/tests/Flow/ETL/Tests/Unit/Function/RoundTest.php
new file mode 100644
index 000000000..02dbf8ff1
--- /dev/null
+++ b/src/core/etl/tests/Flow/ETL/Tests/Unit/Function/RoundTest.php
@@ -0,0 +1,36 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Flow\ETL\Tests\Unit\Function;
+
+use function Flow\ETL\DSL\{float_entry, lit, row};
+use function Flow\ETL\DSL\{ref};
+use Flow\ETL\{Tests\FlowTestCase};
+
+final class RoundTest extends FlowTestCase
+{
+    public function test_round_float() : void
+    {
+        self::assertEquals(
+            10.12,
+            ref('float')->round(lit(2))->eval(row(float_entry('float', 10.123)))
+        );
+
+        self::assertIsFloat(
+            ref('float')->round(lit(2))->eval(row(float_entry('float', 10.123)))
+        );
+    }
+
+    public function test_round_with_precision_0() : void
+    {
+        self::assertEquals(
+            10,
+            ref('float')->round(lit(0))->eval(row(float_entry('float', 10.123)))
+        );
+
+        self::assertIsInt(
+            ref('float')->round(lit(0))->eval(row(float_entry('float', 10.123)))
+        );
+    }
+}