drop procedure if exists schema_change;
delimiter ‘;;‘;
create procedure schema_change() begin
    if not exists( select * from information_schema.`COLUMNS` where TABLE_NAME=‘QYTB_DYAQ‘ and COLUMN_NAME=‘BDCQYWBSM‘) then
        alter table QYTB_DYAQ add BDCQYWBSM CHAR(1);
    end if;
end;;
delimiter ‘;‘;
-- 调用存储过程
call schema_change(); 
drop procedure if exists schema_change;