调整Oracle数据库print_bill表字段BillMKID的顺序，并判断表print_bill是否存在及字段billMKID是否存在

declare
existFlag int;
existColFlag int;
begin 
    select count(1) into existFlag from user_tables where table_name = upper('Print_Bill');
    select count(1) into existColFlag from user_tab_columns where table_name=upper('Print_Bill') and column_name=upper('BillMKID');   
    IF   existFlag>0   THEN
      IF existColFlag=0 THEN
         execute immediate 'alter table PRINT_BILL add BillMKID   varchar(4) default '' '' not null';
      END IF;
      execute immediate 'alter table PRINT_BILL rename to PRINT_BILLTEMP';
      execute immediate '
   CREATE table PRINT_BILL
    (BillMKID    varchar(4) not null,  /*单据所属模块ID*/
    BillID      varchar(50)  primary key not null, /*单据逻辑名称*/
    BillName    varchar(50)  not null,  /*单据显示名称*/
    RecordsPath varchar(200) null ,
    ParamCount  int default 0 /*生成的XML中的参数个数*/
    )';
   execute immediate 'insert into Print_Bill(BillMKID,BillID,BillName,RecordsPath,ParamCount) select BillMKID,BillID,BillName,RecordsPath,ParamCount from Print_Billtemp';
   execute immediate 'drop table Print_Billtemp';
    ELSE
        execute immediate '
          CREATE table PRINT_BILL
      (
        BillMKID    varchar(4) not null,  /*单据所属模块ID*/
      BillID      varchar(50)  primary key not null, /*单据逻辑名称*/
      BillName    varchar(50)  not null,  /*单据显示名称*/
      RecordsPath varchar(200) null ,
      ParamCount  int default 0 /*生成的XML中的参数个数*/
      )';             
    END IF;
END;