Index: server/market.go
===================================================================
--- server/market.go	(revision b715712c7d5d3ee27c932a8a9d8e0a2bc6e85127)
+++ server/market.go	(revision b715712c7d5d3ee27c932a8a9d8e0a2bc6e85127)
@@ -0,0 +1,85 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+
+	"bp_project/server/db"
+)
+
+// Market represents a trading pair.
+type Market struct {
+	ID       string
+	CryptoID string
+	Symbol   string
+	Quote    string
+}
+
+// ListMarkets prints all active markets with their latest price.
+func ListMarkets() {
+	rows, err := db.DB.Query(`
+		SELECT m.id, c.symbol, m.quote_currency,
+		       COALESCE(lp.price, 0) AS price
+		  FROM markets m
+		  JOIN crypto  c  ON c.id = m.crypto_id
+		  LEFT JOIN v_latest_prices lp ON lp.market_id = m.id
+		 WHERE m.is_active = true
+		 ORDER BY c.symbol`)
+	if err != nil {
+		fmt.Println("Error:", err)
+		return
+	}
+	defer rows.Close()
+
+	fmt.Println()
+	fmt.Printf("  %-4s  %-8s  %-5s  %15s\n", "#", "Symbol", "Quote", "Last price")
+	fmt.Println("  -----------------------------------------")
+	i := 1
+	for rows.Next() {
+		var id, sym, quote string
+		var price float64
+		if err := rows.Scan(&id, &sym, &quote, &price); err != nil {
+			fmt.Println("scan error:", err)
+			return
+		}
+		fmt.Printf("  %-4d  %-8s  %-5s  %15.6f\n", i, sym, quote, price)
+		i++
+	}
+}
+
+// ChooseMarket asks the user to pick a market by symbol and returns it.
+func ChooseMarket() (*Market, error) {
+	ListMarkets()
+	sym := prompt("Market symbol (e.g. BTC): ")
+	if sym == "" {
+		return nil, fmt.Errorf("no symbol entered")
+	}
+	var m Market
+	err := db.DB.QueryRow(`
+		SELECT m.id, c.id, c.symbol, m.quote_currency
+		  FROM markets m
+		  JOIN crypto c ON c.id = m.crypto_id
+		 WHERE upper(c.symbol) = upper($1)
+		   AND m.is_active = true
+		 LIMIT 1`, sym,
+	).Scan(&m.ID, &m.CryptoID, &m.Symbol, &m.Quote)
+	if err == sql.ErrNoRows {
+		return nil, fmt.Errorf("market %s not found", sym)
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &m, nil
+}
+
+// LatestPrice returns the last traded price on a market.
+func LatestPrice(marketID string) (float64, error) {
+	var price float64
+	err := db.DB.QueryRow(
+		`SELECT price FROM v_latest_prices WHERE market_id = $1`, marketID,
+	).Scan(&price)
+	if err == sql.ErrNoRows {
+		return 0, fmt.Errorf("no trades yet for this market")
+	}
+	return price, err
+}