Using isBetween

[rajumb502]

  Future<List<Book>> getLimitedBooks(int limit, {int offset = 0})
      =>(select(books)
          ..where((t) => t.srno.isBetweenValues(offset, offset+limit))
              .limit(limit)).get();

I was trying to limit the number of rows I fetch from the DB so that I could paginate in the front end. When I try to use the above, I get this error in the IDE: ''error: This expression has a type of 'void' so its value can't be used. (use_of_void_result at ...) for :

..where((t) => t.srno.isBetweenValues(offset, offset+limit))

The below works without any issues:
Future<List<Book>> getFavoriteBooks() => (select(books)..where((t) => t.favorite.equals(1))).get();

Any inputs on what I could be doing wrong? Error comes with both isBetween and isBetweenValues

[simolus3]

To fix your example, you would also have to use .. before limit:

  Future<List<Book>> getLimitedBooks(int limit, {int offset = 0})
      =>(select(books)
          ..where((t) => t.srno.isBetweenValues(offset, offset+limit))
              ..limit(limit)).get();

But limit has support for offsets builtin, so you don't actually need isBetweenValues at all:

  Future<List<Book>> getLimitedBooks(int limit, {int offset = 0})
      =>(select(books)..limit(limit, offset: offset)).get();

I would recommend to always use orderBy when using limit though. Otherwise the rows returned are not well-defined and might change between sqlite3 versions.

[rajumb502]

Thank you @simolus3 . I read somewhere that using a WHERE clause causes query to run faster than when using LIMIT. Hence the attempt. In my case, srno is the PK and is autoincremented, so I assume I don't have to use orderBy.