orcale增加列脚本

--编号
declare v_cnt number;
 V_SQL VARCHAR2 (500) := '';
begin
 select count(*) into v_cnt from dual where exists(SELECT * FROM USER_TAB_COLUMNS WHERE TABLE_NAME = UPPER('TB_FDN_DEVICEPROJECTHOUSE') AND COLUMN_NAME = 'INFOBH');
   if v_cnt = 0 then
    V_SQL := 'ALTER TABLE TB_FDN_DEVICEPROJECTHOUSE ADD INFOBH VARCHAR2(20)';
    EXECUTE IMMEDIATE V_SQL;
    V_SQL := 'comment on column TB_FDN_DEVICEPROJECTHOUSE.INFOBH is ''编号''';
    EXECUTE IMMEDIATE V_SQL;
end if;
end;