if table is falsey use null in compareTables() (#17642)

2 files changed, 3 insertions, 3 deletions

diff --git a/plugins/API/Filter/DataComparisonFilter.php b/plugins/API/Filter/DataComparisonFilter.php
index 17bec4430d..2a39c607e9 100644
--- a/plugins/API/Filter/DataComparisonFilter.php
+++ b/plugins/API/Filter/DataComparisonFilter.php
@@ -221,7 +221,7 @@ class DataComparisonFilter
             $comparisonSeries[] = $compareMetadata['compareSeriesPretty'];
 
             $compareTable = $this->requestReport($method, $modifiedParams);
-            $this->comparisonRowGenerator->compareTables($compareMetadata, $table, $compareTable);
+            $this->comparisonRowGenerator->compareTables($compareMetadata, $table, empty($compareTable) ? null : $compareTable);
         }
 
         // calculate changes (including processed metric changes)
diff --git a/plugins/API/Filter/DataComparisonFilter/ComparisonRowGenerator.php b/plugins/API/Filter/DataComparisonFilter/ComparisonRowGenerator.php
index da6d5eff75..446eb6cd59 100644
--- a/plugins/API/Filter/DataComparisonFilter/ComparisonRowGenerator.php
+++ b/plugins/API/Filter/DataComparisonFilter/ComparisonRowGenerator.php
@@ -51,7 +51,7 @@ class ComparisonRowGenerator
             $isDatePeriod = $tables->getKeyName() == 'date';
 
             foreach ($childTablesArray as $index => $childTable) {
-                $compareChildTable = isset($compareTablesArray[$index]) ? $compareTablesArray[$index] : null;
+                $compareChildTable = !empty($compareTablesArray[$index]) ? $compareTablesArray[$index] : null;
                 $this->compareTables($compareMetadata, $childTable, $compareChildTable);
             }
 
@@ -82,7 +82,7 @@ class ComparisonRowGenerator
                     $tables->addTable($newTable, $periodLabel);
 
                     // compare with the empty table
-                    $compareTable = $compareTablesArray[$i];
+                    $compareTable = !empty($compareTablesArray[$i]) ? $compareTablesArray[$i] : null;
                     $this->compareTables($compareMetadata, $newTable, $compareTable);
                 }
             }