diff --git a/src/query.zig b/src/query.zig
index 3c9e605..87dd3d6 100644
--- a/src/query.zig
+++ b/src/query.zig
@@ -1595,3 +1595,160 @@ test "compound and predicate narrows via one indexed conjunct" {
         .{ .name = "age", .value = .{ .int = 40 } },
     });
 
+    const preds = [_]Predicate{
+        .{ .eq = .{ .field = "city", .value = .{ .text = "warsaw" } } },
+        .{ .gte = .{ .field = "age", .value = .{ .int = 30 } } },
+    };
+    const results = try table.select(.{ .and_ = &preds });
+    defer freeRows(allocator, results);
+    try std.testing.expectEqual(@as(usize, 1), results.len);
+    try std.testing.expectEqual(@as(i64, 2), results[0].get(pkField).?.int);
+}
+
+test "not and or predicates evaluate via full scan" {
+    const allocator = std.testing.allocator;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    var db = try openTemp(&tmp, allocator);
+    defer db.close();
+
+    var table = try Table.open(&db, allocator, "users");
+    defer table.deinit();
+
+    try table.put(.{ .int = 1 }, &.{.{ .name = "age", .value = .{ .int = 10 } }});
+    try table.put(.{ .int = 2 }, &.{.{ .name = "age", .value = .{ .int = 20 } }});
+    try table.put(.{ .int = 3 }, &.{.{ .name = "age", .value = .{ .int = 30 } }});
+
+    const orPreds = [_]Predicate{
+        .{ .eq = .{ .field = "age", .value = .{ .int = 10 } } },
+        .{ .eq = .{ .field = "age", .value = .{ .int = 30 } } },
+    };
+    const orResults = try table.select(.{ .or_ = &orPreds });
+    defer freeRows(allocator, orResults);
+    try std.testing.expectEqual(@as(usize, 2), orResults.len);
+
+    const inner = Predicate{ .eq = .{ .field = "age", .value = .{ .int = 20 } } };
+    const notResult = try table.select(.{ .not_ = &inner });
+    defer freeRows(allocator, notResult);
+    try std.testing.expectEqual(@as(usize, 2), notResult.len);
+}
+
+test "is_null/is_not_null evaluate against missing fields, explicit none, and present values" {
+    const allocator = std.testing.allocator;
+    var sparse = Row.init(allocator);
+    defer sparse.deinit();
+    try sparse.set("age", .{ .int = 10 });
+
+    var withNone = Row.init(allocator);
+    defer withNone.deinit();
+    try withNone.set("city", .{ .none = {} });
+
+    var withCity = Row.init(allocator);
+    defer withCity.deinit();
+    try withCity.set("city", .{ .text = "warsaw" });
+
+    const isNull = Predicate{ .is_null = "city" };
+    const isNotNull = Predicate{ .is_not_null = "city" };
+
+    try std.testing.expect(isNull.evaluate(&sparse));
+    try std.testing.expect(!isNotNull.evaluate(&sparse));
+    try std.testing.expect(isNull.evaluate(&withNone));
+    try std.testing.expect(!isNotNull.evaluate(&withNone));
+    try std.testing.expect(!isNull.evaluate(&withCity));
+    try std.testing.expect(isNotNull.evaluate(&withCity));
+}
+
+test "is_null selects only sparse rows missing the field, over a full scan" {
+    const allocator = std.testing.allocator;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    var db = try openTemp(&tmp, allocator);
+    defer db.close();
+
+    var table = try Table.open(&db, allocator, "people");
+    defer table.deinit();
+
+    try table.put(.{ .int = 1 }, &.{.{ .name = "city", .value = .{ .text = "warsaw" } }});
+    try table.put(.{ .int = 2 }, &.{.{ .name = "age", .value = .{ .int = 40 } }});
+    try table.put(.{ .int = 3 }, &.{.{ .name = "age", .value = .{ .int = 50 } }});
+
+    var plan = try table.explain(allocator, .{ .is_null = "city" });
+    defer plan.deinit(allocator);
+    try std.testing.expectEqual(PlanKind.full_scan, plan.kind);
+
+    const missing = try table.select(.{ .is_null = "city" });
+    defer freeRows(allocator, missing);
+    try std.testing.expectEqual(@as(usize, 2), missing.len);
+
+    const present = try table.select(.{ .is_not_null = "city" });
+    defer freeRows(allocator, present);
+    try std.testing.expectEqual(@as(usize, 1), present.len);
+
+    // is_null on an indexed field still falls back to full_scan (not
+    // indexable), but the result is unaffected by the index's presence.
+    try table.createIndex("age");
+    const stillMissing = try table.select(.{ .is_null = "city" });
+    defer freeRows(allocator, stillMissing);
+    try std.testing.expectEqual(@as(usize, 2), stillMissing.len);
+}
+
+test "invalid identifiers are rejected" {
+    const allocator = std.testing.allocator;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    var db = try openTemp(&tmp, allocator);
+    defer db.close();
+
+    try std.testing.expectError(error.InvalidIdentifier, Table.open(&db, allocator, ""));
+
+    var table = try Table.open(&db, allocator, "users");
+    defer table.deinit();
+    try std.testing.expectError(error.InvalidIdentifier, table.createIndex("bad\x00field"));
+}
+
+test "selectPage skips offset and stops at limit on a full scan" {
+    const allocator = std.testing.allocator;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    var db = try openTemp(&tmp, allocator);
+    defer db.close();
+
+    var table = try Table.open(&db, allocator, "users");
+    defer table.deinit();
+
+    // Row keys are the pk's order-preserving encoding, so full-scan order
+    // is ascending pk regardless of insertion order.
+    var pk: i64 = 10;
+    while (pk >= 1) : (pk -= 1) {
+        try table.put(.{ .int = pk }, &.{});
+    }
+
+    const page = try table.selectPage(null, .{ .offset = 3, .limit = 4 });
+    defer freeRows(allocator, page);
+    try std.testing.expectEqual(@as(usize, 4), page.len);
+    var expected: i64 = 4;
+    for (page) |r| {
+        try std.testing.expectEqual(expected, r.get(pkField).?.int);
+        expected += 1;
+    }
+}
+
+test "selectPage with limit 0 matches unlimited select" {
+    const allocator = std.testing.allocator;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    var db = try openTemp(&tmp, allocator);
+    defer db.close();
+
+    var table = try Table.open(&db, allocator, "users");
+    defer table.deinit();
+    var pk: i64 = 1;
+    while (pk <= 5) : (pk += 1) try table.put(.{ .int = pk }, &.{});
+
+    const all = try table.select(null);
+    defer freeRows(allocator, all);
+    const page = try table.selectPage(null, .{});
+    defer freeRows(allocator, page);
+    try std.testing.expectEqual(all.len, page.len);
+}
+