diff --git a/block_wrapper.py b/block_wrapper.py
index 818a07d..34f696a 100644
--- a/block_wrapper.py
+++ b/block_wrapper.py
@@ -104,6 +104,10 @@ def construct_sql(input_data):
             sql_template = sql_file.read()
             for key, value in input_data.items():
                 placeholder = f"${key}"
+
+                if value is None:
+                    replacement = "NULL"
+                
                 if isinstance(value, str):
                     value = f"'{value}'"
                 elif isinstance(value, bool):