if ADOQuery1.Locate(FieldName, value,[]) > 0 then ShowMessage('已经存在');
with ADOQuery1 do begin if active then close; open; filtered:=false; if RecordCount>0 then begin First; if Locate(UserName,'ZhangHua'),[loCaseInsensitive]) then begin ShowMessage('已经存在'); end; end; end;
ShowMessage('已经存在');
begin
if active then
close;
open;
filtered:=false;
if RecordCount>0 then
begin
First;
if Locate(UserName,'ZhangHua'),[loCaseInsensitive]) then
begin
ShowMessage('已经存在');
end;
end;
end;