SELECT
    t.Name AS TownName,
    CONVERT(INT,((MCount.MOrders *100) / TCount.TotalCount)) AS MalePercent,
    CONVERT(INT,((FCount.FOrders *100) / TCount.TotalCount)) AS FemalePercent
FROM Towns AS t
LEFT JOIN (SELECT
    o.TownId,
    COUNT(*) AS FOrders
FROM Orders AS o
LEFT JOIN Clients AS c ON c.Id = o.ClientId
WHERE c.Gender = 'F'
GROUP BY o.TownId) AS FCount ON t.Id = FCount.TownId
LEFT JOIN (SELECT
    o.TownId,
    COUNT(*) AS MOrders
FROM Orders AS o
LEFT JOIN Clients AS c ON c.Id = o.ClientId
WHERE c.Gender = 'M'
GROUP BY o.TownId) AS MCount ON MCount.TownId = t.Id
LEFT JOIN (SELECT
    o.TownId,
    COUNT(*) AS TotalCount
FROM Orders AS o
LEFT JOIN Towns AS t ON o.TownId = t.Id
GROUP BY o.TownId) AS TCount ON TCount.TownId = t.Id
GROUP BY t.Name,MCount.MOrders,TCount.TotalCount,FCount.FOrders,t.Id
ORDER BY t.Name,t.Id