Make your dressing: Whisk mayo, lemon juice, sugar, and salt in a small bowl until it looks nice and creamy.
Mix the good stuff: Toss carrots, drained pineapple, raisins, and pecans in your big bowl until everything spreads out evenly.
Coat everything: Pour that creamy dressing over your carrot mix and stir it all up until every piece gets covered.
Let it chill: Cover with plastic wrap and stick it in the fridge for 30 minutes so flavors can mingle together.
Final touch: Stir again before serving and add more mayo if it looks dry from sitting around.