Invalid token SELECT

check out this selection

"SELECT _data, date_added, 0 as isImage FROM video WHERE bucket_id = ?";

• removed bucket_id = ?) on start - this is just wrong, not proper format, doesn't fit to beginning of query...
• removed following UNION as there is no union two selectors at all, just simple query for single video table
• at the end removed unneeded opening bracket (WHERE (bucket_id = ? to WHERE bucket_id = ?)

but note that query is encapsulated and won't accept full single-string sqlite query, you have to split it for parts. variable selection would be "bucket_id = ?" for matching selectionArgs

also note that projection is a bit weird...

String[] projection = new String[]{
        MediaStore.Images.ImageColumns.DATA, MediaStore.Images.ImageColumns.DATE_ADDED, MediaStore.Video.VideoColumns.DATE_ADDED
};

first two values are using MediaStore.Images instead of MediaStore.Video and all three doesn't match params in selection SELECT _data, date_added, 0 as isImage FROM - I see two params and one probably not needed static value

edit: I've just noticed you are selecting by Images - MediaStore.Images.Media.EXTERNAL_CONTENT_URI - but selection is pointing on video column... also I doubt that bucket_id column exists in MediaStore database, there is no such value in static declarations of columns... I would suggest you read a bit about sql and querying, because your snippet looks like every line is comming from another piece of code....