diff --git a/services/nginx/app/classes/department_daily_report_complaints_schema_bootstrap.php b/services/nginx/app/classes/department_daily_report_complaints_schema_bootstrap.php
index 5d2f1fa0..6d18793c 100644
--- a/services/nginx/app/classes/department_daily_report_complaints_schema_bootstrap.php
+++ b/services/nginx/app/classes/department_daily_report_complaints_schema_bootstrap.php
@@ -34,17 +34,21 @@ class department_daily_report_complaints_schema_bootstrap
             ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci"
         );
 
-        $db->query(
-            "ALTER TABLE " . self::TABLE . "
-                ADD COLUMN IF NOT EXISTS wash_date DATE NULL
-                AFTER customer_number"
-        );
+        if (!self::columnExists(self::TABLE, 'wash_date')) {
+            $db->query(
+                "ALTER TABLE " . self::TABLE . "
+                    ADD COLUMN wash_date DATE NULL
+                    AFTER customer_number"
+            );
+        }
 
-        $db->query(
-            "ALTER TABLE " . self::TABLE . "
-                ADD COLUMN IF NOT EXISTS category VARCHAR(64) NULL
-                AFTER wash_date"
-        );
+        if (!self::columnExists(self::TABLE, 'category')) {
+            $db->query(
+                "ALTER TABLE " . self::TABLE . "
+                    ADD COLUMN category VARCHAR(64) NULL
+                    AFTER wash_date"
+            );
+        }
 
         if (!self::indexExists(self::TABLE, self::WASH_DATE_INDEX)) {
             $db->query(
@@ -68,4 +72,17 @@ class department_daily_report_complaints_schema_bootstrap
 
         return $result !== false && $result->num_rows > 0;
     }
+
+    private static function columnExists(string $table, string $column): bool
+    {
+        global $db;
+
+        $table_sql = $db->escape_string($table);
+        $column_sql = $db->escape_string($column);
+        $result = $db->query(
+            "SHOW COLUMNS FROM `$table_sql` LIKE '$column_sql'"
+        );
+
+        return $result !== false && $result->num_rows > 0;
+    }
 }