delphi :
if table1.fiels.findfield('asdfas')=nil then showMessage('not exists!')
mssql:
if Exists(select A.* from syscolumns A inner join sysobjects B on A.id=B.id where B.type = 'U' and
B.name='TableName' and A.name='FieldName')
存在
procedure TForm1.Button1Click(Sender: TObject);
var
StringList: TStringList;
begin
ADOConnection1.GetFieldNames('数据表名', StringList);
if StringList.IndexOf('字段名')>0 then
Showmessage('存在!')
else
Showmessage('不存在!')
end;