i connected esp8266 to port 3 and 4 arduino nano
software serial run
how to connect???
wich library???
As far i know you cannot connect it directly.
You have to have PHP script running on "web server" which will recive data from arduino trought GET or POST methods in php and then php script can make SQL "insert".
From arduino, you have to connect to your wifi.
At first, specify which version of esp8266 you have, it has 13 different versions.
hello electrash...
tnx for your help
at rifst i have esp8266 12e
connect esp8266 to my arduino nano with sotware serial and connect to modem and got ip with at commands
now
how to connect directly? with my data base user and pass ? 
wich library can help me
my sql library just work with arduino wifi
Connecting ESP to Nano is not a great idea. The Nano's 3.3V pin cannot provide enough power for the esp, so an external 3.3V regulator is needed. The Nano is 5V and the ESP is 3.3V, the Nano's outputs could damage the ESP's inputs, so level shifters are needed. But most of all, the ESP is a much faster mcu with far more ram and flash memory. Using it as a dumb slave for a Nano is like towing a Ferrari with a golf cart.
I suggest you consider removing the Nano from the circuit and programming code into the esp directly. Then you can use the MySQL library. The easiest type of esp to use like this is a Wemos Mini. It has 3.3V regulator, usb socket and usb serial chip built-in, making it almost as easy to use as a Nano. If the esp does not have enough pins, there are ways to fix that. Post your schematic and we can advise you.