compare with null (mysql)

[par4doxon]

I want to get that the query's result in the lastlogin is NULL or not.

Here is the code:

  
-- Query 
lastLoginData = mysql:query("SELECT `lastlogin` FROM `accounts` WHERE `id`='" .. tostring(accountID) .. "'") 
-- gets the lastlogin value (its [i]NULL[/i] in the table, and the type is [i]datetime[/i]) 
local lastLogin = tostring(mysql:result(lastLoginData, 1, 1)) 
-- writes out the lastLogin, but.. weird result: [2013-07-06 15:44:45] [Output] : userdata: 0086707C 
outputChatBox(lastLogin, getRootElement(), 255, 0, 0) 
-- after this, I want to compare this lastlogin with something, to get that this is [i]NULL[/i] or not. 
-- like this: 
if (lastLogin == mysql:null()) then -- but this isnt working 
-- todo 
end 
  

Thanks in advance!

[dudeks]

mysql:result(lastLoginData, 1, 1) 

Change to:

lastLoginData:result(1, 1) 

And

mysql:null() 

to

mysql_null() 

[par4doxon]

mysql:result(lastLoginData, 1, 1) 

Change to:

lastLoginData:result(1, 1) 

And

mysql:null() 

to

mysql_null() 

It says:

[2013-07-06 20:42:56] ERROR: accounts\s_characters.lua:98: attempt to index global 'lastLoginData' (a number value)

The 98th line is:

local lastLogin = lastLoginData:result(1, 1) 

[dudeks]

Are you using this module?

https://wiki.multitheftauto.com/wiki/Modules/MTA-MySQL

If it's not work, try to use your code

local lastLogin = tostring(mysql:result(lastLoginData, 1, 1)) 

In my test with using MTA-MySQL module.

lastLoginData = mysql:query("SELECT `lastlogin` FROM `accounts` WHERE `id`='1'") 
    print(tostring("test1")) 
    local lastLogin = tostring(lastLoginData:result(1, 1)) 
    print(tostring("test2")) 
    outputChatBox(lastLogin, getRootElement(), 255, 0, 0) 
    print(tostring("test3")) 
    if (tostring(lastLogin) == tostring(mysql_null())) then -- but this isnt working 
        print(tostring("lastlogin == mysql_null")) 
    else 
        print(tostring("lastlogin ~= mysql_null"))   
    end 
    print("lastLoginData: "..tostring(lastLoginData)) 
    print("lastLogin: "..tostring(lastLogin)) 
    print("mysql_null: "..tostring(mysql_null())) 

test1 
test2 
test3 
lastlogin ~= mysql_null 
lastLoginData: MySQL result (#107) 
lastLogin: gsgsg 
mysql_null: userdata: 038C0138 

Is you query working?

[par4doxon]

Are you using this module?

https://wiki.multitheftauto.com/wiki/Modules/MTA-MySQL

If it's not work, try to use your code

local lastLogin = tostring(mysql:result(lastLoginData, 1, 1)) 

In my test with using MTA-MySQL module.

lastLoginData = mysql:query("SELECT `lastlogin` FROM `accounts` WHERE `id`='1'") 
    print(tostring("test1")) 
    local lastLogin = tostring(lastLoginData:result(1, 1)) 
    print(tostring("test2")) 
    outputChatBox(lastLogin, getRootElement(), 255, 0, 0) 
    print(tostring("test3")) 
    if (tostring(lastLogin) == tostring(mysql_null())) then -- but this isnt working 
        print(tostring("lastlogin == mysql_null")) 
    else 
        print(tostring("lastlogin ~= mysql_null"))   
    end 
    print("lastLoginData: "..tostring(lastLoginData)) 
    print("lastLogin: "..tostring(lastLogin)) 
    print("mysql_null: "..tostring(mysql_null())) 

test1 
test2 
test3 
lastlogin ~= mysql_null 
lastLoginData: MySQL result (#107) 
lastLogin: gsgsg 
mysql_null: userdata: 038C0138 

Is you query working?

Yes, I'm using that module.

First line:

local mysql = exports.mysql 

I changed back to this:

local lastLogin = tostring(mysql:result(lastLoginData, 1, 1)) 

And this doesn't give me error.

And now it's working!

This was the problem:

if (lastLogin == mysql:null()) then 

And I changed to this: (from your code)

if (lastLogin == tostring(mysql_null())) then 

Thanks!