update of posotion by trade his

internal/database/company.go

@@ -8,6 +8,22 @@ import (
 	_ "github.com/mattn/go-sqlite3"
 )
 
+func GetCompanyBySymbol(db *sql.DB, symbol string) (*model.Company, error) {
+	var c model.Company
+	err := db.QueryRow(
+		`SELECT id, symbol, shares_outstanding, price, currency_id FROM companies WHERE symbol = ?`,
+		symbol,
+	).Scan(&c.ID, &c.Symbol, &c.SharesOutstanding, &c.Price, &c.CurrencyID)
+
+	if err == sql.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("query company: %w", err)
+	}
+	return &c, nil
+}
+
 func GetCompanyByID(db *sql.DB, id int) (*model.Company, error) {
 	var c model.Company
 	err := db.QueryRow(