diff --git a/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php b/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php
index b2b0e669..3c8b176f 100644
--- a/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php
+++ b/src/PhpSpreadsheet/Calculation/Database/DatabaseAbstract.php
@@ -95,7 +95,7 @@ abstract class DatabaseAbstract
         foreach ($criteria as $key => $criterion) {
             foreach ($criterion as $field => $value) {
                 $criterionName = $criteriaNames[$field];
-                if ($value !== null && $value !== '') {
+                if ($value !== null) {
                     $condition = self::buildCondition($value, $criterionName);
                     $baseQuery[$key][] = $condition;
                 }
@@ -104,12 +104,12 @@ abstract class DatabaseAbstract
 
         $rowQuery = array_map(
             function ($rowValue) {
-                return (count($rowValue) > 1) ? 'AND(' . implode(',', $rowValue) . ')' : $rowValue[0];
+                return (count($rowValue) > 1) ? 'AND(' . implode(',', $rowValue) . ')' : ($rowValue[0] ?? '');
             },
             $baseQuery
         );
 
-        return (count($rowQuery) > 1) ? 'OR(' . implode(',', $rowQuery) . ')' : $rowQuery[0];
+        return (count($rowQuery) > 1) ? 'OR(' . implode(',', $rowQuery) . ')' : ($rowQuery[0] ?? '');
     }
 
     private static function buildCondition($criterion, string $criterionName): string
diff --git a/src/PhpSpreadsheet/Calculation/Functions.php b/src/PhpSpreadsheet/Calculation/Functions.php
index aea2323e..9b56aad4 100644
--- a/src/PhpSpreadsheet/Calculation/Functions.php
+++ b/src/PhpSpreadsheet/Calculation/Functions.php
@@ -251,7 +251,7 @@ class Functions
         $condition = self::flattenSingleValue($condition);
 
         if ($condition === '') {
-            $condition = '=""';
+            return '=""';
         }
         if (!is_string($condition) || !in_array($condition[0], ['>', '<', '='])) {
             $condition = self::operandSpecialHandling($condition);
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/MathTrig/SumIfTest.php b/tests/PhpSpreadsheetTests/Calculation/Functions/MathTrig/SumIfTest.php
index 39ac9a66..93c2ae32 100644
--- a/tests/PhpSpreadsheetTests/Calculation/Functions/MathTrig/SumIfTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/MathTrig/SumIfTest.php
@@ -20,8 +20,7 @@ class SumIfTest extends AllSetupTeardown
         $sheet->fromArray($array1, null, 'A1', true);
         $maxARow = count($array1);
         $firstArg = "A1:A$maxARow";
-        //$secondArg = is_string($condition) ? "\"$condition\"" : $condition;
-        $sheet->getCell('B1')->setValue($condition);
+        $this->setCell('B1', $condition);
         $secondArg = 'B1';
         if (empty($array2)) {
             $sheet->getCell('D1')->setValue("=SUMIF($firstArg, $secondArg)");
diff --git a/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/AverageIf2Test.php b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/AverageIf2Test.php
new file mode 100644
index 00000000..1899239f
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Calculation/Functions/Statistical/AverageIf2Test.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Calculation\Functions\Statistical;
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PHPUnit\Framework\TestCase;
+
+class AverageIf2Test extends TestCase
+{
+    public function testAVERAGEIF(): void
+    {
+        $table = [
+            ['n', 1],
+            ['', 2],
+            ['y', 3],
+            ['', 4],
+            ['n', 5],
+            ['n', 6],
+            ['n', 7],
+            ['', 8],
+            [null, 9],
+        ];
+
+        $spreadsheet = new Spreadsheet();
+        $sheet = $spreadsheet->getActiveSheet();
+        $sheet->fromArray($table, null, 'A1', true);
+        $sheet->getCell('C1')->setValue('=AVERAGEIF(A:A,"",B:B)');
+        $sheet->getCell('C2')->setValue('=AVERAGEIF(A:A,,B:B)');
+        $sheet->getCell('C3')->setValue('=AVERAGEIF(A:A,"n",B:B)');
+        $sheet->getCell('C4')->setValue('=AVERAGEIF(A:A,"y",B:B)');
+        $sheet->getCell('C5')->setValue('=AVERAGEIF(A:A,"x",B:B)');
+
+        self::assertEqualsWithDelta(5.75, $sheet->getCell('C1')->getCalculatedValue(), 1E-12);
+        self::assertEquals('#DIV/0!', $sheet->getCell('C2')->getCalculatedValue());
+        self::assertEqualsWithDelta(4.75, $sheet->getCell('C3')->getCalculatedValue(), 1E-12);
+        self::assertEqualsWithDelta(3, $sheet->getCell('C4')->getCalculatedValue(), 1E-12);
+        self::assertEquals('#DIV/0!', $sheet->getCell('C5')->getCalculatedValue());
+        $spreadsheet->disconnectWorksheets();
+    }
+}
diff --git a/tests/data/Calculation/MathTrig/SUMIF.php b/tests/data/Calculation/MathTrig/SUMIF.php
index 0a6cfbdc..a427624f 100644
--- a/tests/data/Calculation/MathTrig/SUMIF.php
+++ b/tests/data/Calculation/MathTrig/SUMIF.php
@@ -150,4 +150,22 @@ return [
         'North ?',
         [[36693], [22100], ['=3/0'], [34440], [29889], [50090], [32080], [45500]],
     ],
+    [
+        23,
+        [['n'], [''], ['y'], [''], ['n'], ['n'], ['n'], [''], []],
+        '',
+        [[1], [2], [3], [4], [5], [6], [7], [8], [9]],
+    ],
+    [
+        0,
+        [['n'], [''], ['y'], [''], ['n'], ['n'], ['n'], [''], []],
+        null,
+        [[1], [2], [3], [4], [5], [6], [7], [8], [9]],
+    ],
+    [
+        19,
+        [['n'], [''], ['y'], [''], ['n'], ['n'], ['n'], [''], []],
+        'n',
+        [[1], [2], [3], [4], [5], [6], [7], [8], [9]],
+    ],
 ];