Question

下面Delphi代码为何一运行，编译器就报:Incompatible types:'String'and'TDateTime'？

procedure Ttixg_Form.DBGrid1CellClick(Column: TColumn);
var
sqlstr:string;
riqi:TDateTime;
begin
hint := column.Field.AsString;
riqi:=DateTimePicker1.DateTime;
sqlstr:='select * from t_xin where(BIRTHDAY="'+riqi+'")';
ADOQuery1.Close;
ADOQuery1.SQL.Clear;
ADOQuery1.SQL.Add(sqlstr);
ADOQuery1.Open;
//BIRTHDAY字段定义为日期型

Answer 1

sqlstr中riqi不是string类型的，先将riqi用
DateTimeToStr()转换成字符串就可以了。