diff --git a/src/Type/Doctrine/Query/QueryResultTypeWalker.php b/src/Type/Doctrine/Query/QueryResultTypeWalker.php
index c186a5e3..14519922 100644
--- a/src/Type/Doctrine/Query/QueryResultTypeWalker.php
+++ b/src/Type/Doctrine/Query/QueryResultTypeWalker.php
@@ -933,12 +933,29 @@ public function walkAggregateExpression($aggExpression): string
 		switch ($aggExpression->functionName) {
 			case 'MAX':
 			case 'MIN':
+				$type = $this->unmarshalType(
+					$this->walkSimpleArithmeticExpression($aggExpression->pathExpression)
+				);
+
+				return $this->marshalType(TypeCombinator::addNull($type));
+
 			case 'AVG':
+				$type = $this->unmarshalType(
+					$this->walkSimpleArithmeticExpression($aggExpression->pathExpression)
+				);
+
+				$type = TypeCombinator::union($type, $type->toFloat());
+				$type = TypeUtils::generalizeType($type, GeneralizePrecision::lessSpecific());
+
+				return $this->marshalType(TypeCombinator::addNull($type));
+
 			case 'SUM':
 				$type = $this->unmarshalType(
 					$this->walkSimpleArithmeticExpression($aggExpression->pathExpression)
 				);
 
+				$type = TypeUtils::generalizeType($type, GeneralizePrecision::lessSpecific());
+
 				return $this->marshalType(TypeCombinator::addNull($type));
 
 			case 'COUNT':
diff --git a/tests/Type/Doctrine/Query/QueryResultTypeWalkerTest.php b/tests/Type/Doctrine/Query/QueryResultTypeWalkerTest.php
index 27d1acab..ea1e0aea 100644
--- a/tests/Type/Doctrine/Query/QueryResultTypeWalkerTest.php
+++ b/tests/Type/Doctrine/Query/QueryResultTypeWalkerTest.php
@@ -681,6 +681,82 @@ public function getTestData(): iterable
 			',
 		];
 
+		yield 'aggregate on literal' => [
+			$this->constantArray([
+				[
+					new ConstantIntegerType(1),
+					TypeCombinator::union(
+						new ConstantStringType('1'),
+						new ConstantIntegerType(1),
+						new NullType()
+					),
+				],
+				[
+					new ConstantIntegerType(2),
+					TypeCombinator::union(
+						new ConstantStringType('0'),
+						new ConstantIntegerType(0),
+						new ConstantStringType('1'),
+						new ConstantIntegerType(1),
+						new NullType()
+					),
+				],
+				[
+					new ConstantIntegerType(3),
+					TypeCombinator::union(
+						new ConstantStringType('1'),
+						new ConstantIntegerType(1),
+						new NullType()
+					),
+				],
+				[
+					new ConstantIntegerType(4),
+					TypeCombinator::union(
+						new ConstantStringType('0'),
+						new ConstantIntegerType(0),
+						new ConstantStringType('1'),
+						new ConstantIntegerType(1),
+						new NullType()
+					),
+				],
+				[
+					new ConstantIntegerType(5),
+					TypeCombinator::union(
+						$this->intStringified(),
+						new FloatType(),
+						new NullType()
+					),
+				],
+				[
+					new ConstantIntegerType(6),
+					TypeCombinator::union(
+						$this->intStringified(),
+						new FloatType(),
+						new NullType()
+					),
+				],
+				[
+					new ConstantIntegerType(7),
+					TypeCombinator::addNull($this->intStringified()),
+				],
+				[
+					new ConstantIntegerType(8),
+					TypeCombinator::addNull($this->intStringified()),
+				],
+			]),
+			'
+				SELECT		MAX(1),
+							MAX(CASE WHEN m.intColumn = 0 THEN 1 ELSE 0 END),
+							MIN(1),
+							MIN(CASE WHEN m.intColumn = 0 THEN 1 ELSE 0 END),
+							AVG(1),
+							AVG(CASE WHEN m.intColumn = 0 THEN 1 ELSE 0 END),
+							SUM(1),
+							SUM(CASE WHEN m.intColumn = 0 THEN 1 ELSE 0 END)
+				FROM		QueryResult\Entities\Many m
+			',
+		];
+
 		yield 'literal' => [
 			$this->constantArray([
 				[