Mysql database, workbench, error, SQL format error?

The database creation is stuck with the following code, and the last three lines are marked in red. What is the problem? Beginifnew. item_type_id & lt; & gt; old. item_type_idornew.measure_type_id & lt; & gt; old. measure_type_idornew.per_quantity & lt; & gt; old. per_quantityornew.total_weight & lt; & gt; old. total_weightornew.unit_price & mysqlworkbenchsql database creation

Database creation is stuck
The code is as follows. the last three lines show the red ×.
What is the problem?
Begin
If new. item_type_id <> old. item_type_id
Or new. measure_type_id <> old. measure_type_id
Or new. per_quantity <> old. per_quantity
Or new. total_weight <> old. total_weight
Or new. unit_price <> old. unit_price
Or new. enabled_flag <> old. enabled_flag then
Insert into mtl_item_price_his
Set item_id = old. item_id
, Change_date = now ()
, Unit_price = old. unit_price
, Item_type_id = old. item_type_id
, Measure_type_id = old. measure_type_id
, Per_quantity = old. per_quantity
, Total_weight = old. total_weight
, Description = old. description
, Creation_date = now ()
, Created_by = old. last_updated_by;
END if;
End;