hi,
I need use TDataset.Lookup, I know how to do this, but need help about,
result field is blob field
Var
  V : Variant;
BlobField : TBlobField;
..
V := QUE_.Lookup('UNQ_ID', H_ID, 'BIN_DATA');// BIN_DATA type is TBlobField
if V=Null then Exit;
   BlobField := TBlobField(V);//<- Problem is here !!!
//  if QUE_.Locate('UNQ_ID', VarArrayOf([H_ID]), [])
//   then BlobField := TBlobField(QUE_.FieldByName('BIN_DATA'))
//   else Exit;

I'm looking for fast way

FreeMan wrote

I need use TDataset.Lookup, I know how to do this, but need help about, result field is blob field

The whole idea of blob-fields is that they are not loaded into the dataset-in-memory.

They are only read from the database if they are specifically read.

So, no, you can not use lookup to access them.

Joost.

Thank you,
I added new Tquery and use where clause and result one tblobfield. I found best and fast way this.