Question

DELPHI编译报错Incompatible types: 'TStrings' and 'String'，不知道错在哪里

procedure TForm1.Button1Click(Sender: TObject);
var
PALLET_NO:string;
begin
adoquery1.SQL:='select pallet_no,carton_no,serial_number,qc_no from sajet.g_sn_status where pallet_no=:PALLET_NO';
ADOQUERY1.Parameters.ParamByName('PALLET_NO').Value:=TRIM(edit1.text);
ADOQuery1.Open;
end;
end.

Answer 1

adoquery1.SQL.Text := 'SELECT ******'
adoquery1.SQL是TStrings类型，所以不可以直接赋值为string

Answer 2

adoquery1.SQL改成
adoquery1.SQL.Text

还有，建议在打开之前先关闭和清空，建议这样写
procedure TForm1.Button1Click(Sender: TObject);
var
PALLET_NO:string;
begin
adoquery1.Close; //加上
adoquery1.Sql.Clear; //加上
adoquery1.SQL.Text.Add('select pallet_no,carton_no,serial_number,qc_no from sajet.g_sn_status where pallet_no=:PALLET_NO');
ADOQUERY1.Parameters.ParamByName('PALLET_NO').Value:=TRIM(edit1.text);
ADOQuery1.Open;
end;
end.