Handle non-nullable expressions in update bindings

This update ensures non-nullable expressions are unified with nullable data types where required, maintaining consistency in type handling. Additionally, it includes error logging for cases when data type retrieval fails, improving debugging visibility.

Author: loloxwg

src/query/sql/src/planner/binder/bind_mutation/update.rs

@@ -171,9 +171,23 @@ impl Binder {
             .iter()
             .flat_map(|eval| {
                 eval.update.iter().flat_map(|update| {
-                    update
-                        .values()
-                        .flat_map(|expr| expr.used_columns().into_iter())
+                    update.values().flat_map(|expr| {
+                        let processed_expr = expr
+                            .data_type()
+                            .map(|data_type| {
+                                if !data_type.is_nullable_or_null() {
+                                    expr.clone()
+                                        .unify_to_data_type(&data_type.nest_wrap_nullable())
+                                } else {
+                                    expr.clone()
+                                }
+                            })
+                            .unwrap_or_else(|_| {
+                                log::error!("Failed to get data type for expression");
+                                expr.clone()
+                            });
+                        processed_expr.used_columns().into_iter()
+                    })
                 })
             })
             .chain(mutation.required_columns.iter().copied())