How can I make players keep credits upon leaving the server

[Rolad]

	

    require("mysql")
    AddCSLuaFile("autorun/client/creditsmenu.lua")
    local ITEM
     
    function RegisterEmeraldsItem(tb)
            ITEM[string.upper(tb.Name)] = tb
            print(Format("Emeralds Credit System -> Registered item %s",tb.Name))
    end
     
    local function LoadEmeraldCreditModules()
            ITEM = {}
            local files = file.FindInLua("EmeraldCredits/sv_modules/*.lua")
            for k, v in pairs(files) do
                    include("EmeraldCredits/sv_modules/"..v)
            end
    end
    LoadD3CreditModules()
     
    concommand.Add("EmeraldCredits_Reload",function(p,c,a)
            if p and p:IsValid() then
                    if p:IsSuperAdmin() then
                            LoadEmeraldCreditModules()
                            for k,v in pairs(player.GetAll()) do
                                    v:ChatPrint("Emerald Credits was reloaded...")
                            end
                            print("Emerald Credits was reloaded...")
                    end
            else
                    LoadEmeraldCreditModules()
                    for k,v in pairs(player.GetAll()) do
                            v:ChatPrint("Emerald Credits was reloaded...")
                    end
                    print("Emerald Credits was reloaded...")
            end
    end)
     
    concommand.Add("EmeraldCredits",function(p,c,a)
            if a[1] then
                    if string.upper(a[1]) == "BUY" then
                            if a[2] then
                                    local i = string.upper(a[2])
                                    if ITEM[i] then
                                            local db, e = mysql.connect("localhost","donations","donations","donations")
                                            if db == 0 then
                                                    print(e)
                                            else
                                                    local tb, succ, e = mysql.query(db,Format("SELECT * FROM `Emeraldpoints` WHERE SteamID=%q",p:SteamID()))
                                                    if succ then
                                                            if tb then
                                                                    local bal = tonumber(tb[1][3])
                                                                    if bal >= ITEM[i].Cost then
                                                                            if (ITEM[i].Eligible(p)) then
                                                                                    tb, succ, e = mysql.query(db,Format("UPDATE `Emeraldpoints` SET Points=Points-%s WHERE SteamID=%q",ITEM[i].Cost,p:SteamID()))
                                                                                    if !succ then print(e) end
                                                                                    p:ChatPrint(Format("You bought %s for %s credits!",ITEM[i].Name,ITEM[i].Cost))
                                                                                    p:ChatPrint(Format("Your account balance is now %s credits.",bal-ITEM[i].Cost))
                                                                                    ITEM[i].Give(p)
                                                                                    for k,v in pairs(player.GetAll()) do
                                                                                            if v != p then
                                                                                                    v:ChatPrint(Format("%s just bought %s with their Emerald Credits!",p:Name(),ITEM[i].Name))
                                                                                            end
                                                                                    end
                                                                            else
                                                                                    p:ChatPrint(Format("You are not currently eligible to purchase %s!", item[i].Name))
                                                                            end
                                                                    else
                                                                            p:ChatPrint(Format("You don't have enough credits to purchase %s!",ITEM[i].Name))
                                                                    end
                                                            end
                                                    else
                                                            print(e)
                                                    end
                                            end
                                            mysql.disconnect(db)   
                                    end
                            end
                    end
            end
    end)
     
    hook.Add("PlayerInitialSpawn","EmeraldCredits",function(p)
            local db, e = mysql.connect("localhost","donations","donations","donations")
            if db == 0 then
                    print(e)
            else
                    local tb, succ, e = mysql.query(db,Format("SELECT COUNT(*) FROM `Emeraldpoints` WHERE SteamID=%q",p:SteamID()))
                    if succ then
                            if tb then
                                    if tonumber(tb[1][1]) < 1 then
                                            tb, succ, e = mysql.query(db,Format("INSERT INTO `Emeraldpoints` (`SteamID`,`Points`) VALUES(%q,'0')",p:SteamID()))
                                            if !succ then print(e) end
                                    else
                                            tb, succ, e = mysql.query(db,Format("SELECT * FROM `Emeraldpoints` WHERE SteamID=%q",p:SteamID()))
                                            if succ then
                                                    timer.Simple(5,function()
                                                            if p and p:IsValid() then
                                                                    p:ChatPrint(Format("Welcome %s! You have %s credits on your account to spend.",p:Name(),tb[1][3]))
                                                                    p:ChatPrint("Say /emerald to access the credit store now!")
                                                            end
                                                    end)
                                            else
                                                    print(e)
                                            end
                                    end
                            end
                    else
                            print(e)
                    end
            end
            mysql.disconnect(db)
    end)
     
    concommand.Add("GetEmeraldCreditInfo",function(p,c,a)
            if !p or !p:IsValid() then return end
            umsg.Start("EmeraldCreditItems",p)
                    umsg.Short(table.Count(ITEM))
                    local k,v
                    for k,v in pairs(ITEM) do
                            umsg.String(v.Name)
                            umsg.String(tostring(v.Cost))
                            umsg.String(v.Description)
                    end
            umsg.End()
     
            umsg.Start("EmeraldCreditBalance",p)
                    local db, e = mysql.connect("localhost","donations","donations","donations")
                    if db == 0 then
                            print(e)
                    else
                            local tb, succ, e = mysql.query(db,Format("SELECT COUNT(*) FROM `Emeraldpoints` WHERE SteamID=%q",p:SteamID()))
                            if succ then
                                    if tb then
                                            tb, succ, e = mysql.query(db,Format("SELECT * FROM `Emeraldpoints` WHERE SteamID=%q",p:SteamID()))
      

[Jeezy]

You seem to already know how to work with mySQL, so hooking onto the PlayerDisconnected or EntityRemoved should be cake.. unless that's not your code.