SQL Server和Access分别可取得随机记录

withtk_querydo

begin

Close;

sql.clear;

sql.Add('selecttop'+inttostr
(st_count)+'tk.ID,标准答案from题库表tk');

sql.Add('wherepidisnullandtk.题型=
'+quotedstr(tx)+'andtk.知识点='+quotedstr(zsd));

sql.add('andtk.难易度='+quotedstr(nyd)+
'andtk.课程号='+quotedstr(kcdm)+'orderbynewid()');

Open;

end;

functionTTest_Srv_RDataForm.Get_Random_ID
(constkcdm,tx,zsd,nyd,t_count:string):string;

var

sl:TStrings;

i,ii,kk:integer;

begin

try

Result:='';

sl:=TStringList.Create;

withTADOQuery.Create(nil)do

begin

try

Connection:=Adoconnection1;

SQL.Text:='selectIDfrom题库表
wherepidisnulland题型='+quotedstr(tx)+

'and知识点='+quotedstr(zsd)+'and难易度='+quotedstr(nyd)+

'and课程号='+quotedstr(Kcdm);

Open;

whilenotEofdo

begin

sl.Add(Fields[0].AsString);

Next;

end;

Close;

finally

Free;

end;

end;//endwith....

ifsl.Count=0then

Exit;

fori:=0toStrToIntDef(t_count,0)-1do

begin

kk:=sl.Count;//随机因子

Randomize;

ii:=Random(kk);//取得随机数

ifResult=''then

Result:=sl.Strings[ii]

else

Result:=Result+','+sl.Strings[ii];

sl.Delete(ii);
//为了避免有可能出现的重复，此ID被抽取过后把它删了

ifsl.Count=0then
//如果无题可抽了退出循环

Break;

end;

Result:='('+Result+')';
//给结果串前后加上(......)，最终形成(24,36,5,89,72,3,6,1....)的串样

finally

sl.Free;



end;

end;

//=================课程号,题型,知识点,难易度,题量

functionTTest_Srv_RDataForm.Get_Random_Sql
(constkcdm,tx,zsd,nyd,t_count:string):string;

begin

Result:=Get_Random_ID(kcdm,tx,zsd,nyd,t_count);

ifResult<>''then

Result:='selecttop'+t_count+'tk.ID,
标准答案from题库表tkwhereidin'+Result

else

Result:='selecttop'+t_count+'tk.ID,
标准答案from题库表tkwhere1=1';

end;

//以下为调用上述函数生成随机抽题的代码片断

.......

withtk_querydo

begin

Close;

sql.Clear;

sql.Text:=Get_Random_Sql(Kcdm,tx_str,zsd_str,nyd_str,txzsd_count_str);

Open;
end;