MongoDB vs PostgreSQL: NoSQL vs Relational with JSONB

// MongoDB Aggregation Pipeline ($unwind + $match)
db.orders.aggregate([
  { $unwind: "$items" },
  { 
    $match: { 
      "items.category": "Electronics",
      "items.price": { $gte: 500 }
    }
  },
  {
    $group: {
      _id: "$customer_id",
      total_spent: { $sum: "$items.price" },
      item_count: { $sum: 1 }
    }
  }
])

-- PostgreSQL JSONB Array Expansion (jsonb_to_recordset)
SELECT 
    o.customer_id,
    SUM((item->>'price')::numeric) AS total_spent,
    COUNT(*) AS item_count
FROM orders o,
jsonb_array_elements(o.order_data->'items') AS item
WHERE item->>'category' = 'Electronics'
  AND (item->>'price')::numeric >= 500
GROUP BY o.customer_id;