diff --git a/src/sql/src/statements.rs b/src/sql/src/statements.rs
index 531051bf62..4e15d15ea4 100644
--- a/src/sql/src/statements.rs
+++ b/src/sql/src/statements.rs
@@ -260,10 +260,11 @@ pub fn column_def_to_schema(column_def: &ColumnDef, is_time_index: bool) -> Resu
 pub fn sql_column_def_to_grpc_column_def(col: ColumnDef) -> Result<api::v1::ColumnDef> {
     let name = col.name.value.clone();
     let data_type = sql_data_type_to_concrete_data_type(&col.data_type)?;
-    let nullable = col
+
+    let nullable = !col
         .options
         .iter()
-        .any(|o| matches!(o.option, ColumnOption::Null));
+        .any(|o| matches!(o.option, ColumnOption::NotNull));
 
     let default_constraint = parse_column_default_constraint(&name, &data_type, &col.options)?
         .map(ColumnDefaultConstraint::try_into) // serialize default constraint to bytes