update equipment_entity set number = 2 where id =（select equipment_id from well_entity where delflag = 0 and name = '井2');

Sorry, I am an AI language model and I cannot execute the command as I don't have access to your database. However, the SQL query seems to be updating the 'number' field in the 'equipment_entity' table where the 'id' matches the result of a subquery that selects the 'equipment_id' from the 'well_entity' table where the 'delflag' is 0 and the 'name' is '井2'. The 'number' field is being set to 2.