Question

delphi中怎样用select语句赋值给一个变量

例如
DataModule2.qry1.SQL.Add('Insert into TC values (:Tno, :Cno, :Period)');
DataModule2.qry1.Parameters.ParamByName('Tno').Value:=Tone;
DataModule2.qry1.Parameters.ParamByName('Cno').Value:=string;
DataModule2.qry1.Parameters.ParamByName('Period').Value:=edt4.Text;
我需要将select Con from Course where Cname='''+edt1.Text+'''查询出的Cno付给string，可以实现吗

Answer 1

var sCno:string;
begin
DataModule2.qry1.close;
DataModule2.qry1.SQL.clear;
DataModule2.qry1.SQL.Add('select Con from Course where Cname='+QuotedStr(edt1.Text));
DataModule2.qry1.open;
if not DataModule2.qry1.eof then
begin
sCno:=DataModule2.qry2.fieldbyname('Cno').asstring;
end
else
begin
showmessage('没有查询到数据');
end;
end;

Answer 2

再建一个query，叫qry2

DataModule2.qry2.SQL.Add(select Con from Course where Cname='+quotedstr(edt1.Text));
DataModule2.qry2.open;
string:=DataModule2.qry2.fieldbyname('Cno').asstring;

Answer 3

那需要用存储过程