Examples

Creating a SQL table

SQL Code

CREATE TABLE userData(  -- Create a table called 'userData'
    userId VARCHAR NOT NULL,  -- Make the first column in the table called 'userId' as a data type 'VARCHAR' and make it 'NOT NULL'
    gold INT(10),  -- Make the second column in the table called 'gold' as data type 'INT' however only allow 10 digit numbers eg. 1000000000
    wood INT(10),  -- Make the second column in the table called 'wood' as data type 'INT' however only allow 10 digit numbers eg. 1000000000
    gems INT(10),  -- Make the second column in the table called 'gems' as data type 'INT' however only allow 10 digit numbers eg. 1000000000

    PRIMARY KEY(userId)  -- Make a primary key and assign it to 'userId'
)

Lua code

local DataStore3 = require(game:GetService("ServerScriptService").DataStore3Libary);

local payload = [[
CREATE TABLE userData(
    userId VARCHAR NOT NULL,
    gold INT(10),
    wood INT(10),
    gems INT(10),

    PRIMARY KEY(userId)
)
]]
local response = DataStore3.GetPayload(payload)

Adding Player to database on join

local DataStore3 = require(game:GetService("ServerScriptService").DataStore3Libary);

local Players = game:GetService("Players")

Players.PlayerAdded:Connect(function(player)  -- Player Join function
	local userid = player.UserId  -- Get UserId of joined player
	local payload = "SELECT * FROM userData WHERE userId ='"..userid.."'"  -- Select all from userdata table where userId = players userid (SQL CODE)
	local response = DataStore3.GetPayload(payload)  -- Send the post request to the server

	if response.Response == nil then  -- If the responce is nil (Meaning the player isnt already in the data base)
		local payload = "INSERT INTO userData VALUES ('"..userid.."', '0', '0', '0')"  -- Add the player to the database making the first value the userId (SQL CODE)
		local response = DataStore3.PostPayload(payload)  -- Send the post request to the server
	else  -- If the user is in the databse
		local payload = "SELECT * FROM userData WHERE userId = '"..player.UserId.."'"  -- Select all data from the userdata table where userId = players userid (SQL CODE) 
		local response = DataStore3.GetPayload(payload)  -- Send the get request to the server
		
		-- When getting a response there are two parts the table 'response.Response[a][b]' A & B a is the selector for example if a was equal to 1 you would 
		-- get the response code (1 is success and 0 is an error) if a was equal to 2 you would get the SQL response for this example (userId, Gold, Wood, Gems)

		player.leaderstats.Gold.Value = response.Response[1][2]  -- Make the leaderstat of the player equal to the usersData (Gold, 2nd column in row)
		player.leaderstats.Gems.Value = response.Response[1][4]  -- Make the leaderstat of the player equal to the usersData (Gems, 4nd column in row)
		player.Inventory.Wood.Value = response.Response[1][3]  -- Make the leaderstat of the player equal to the usersData (Wood, 3nd column in row)
	end
end)

Save Player Data on leave

local DataStore3 = require(game:GetService("ServerScriptService").DataStore3Libary);

local Players = game:GetService("Players")


Players.PlayerRemoving:Connect(function(player)  -- Player Leave function
	gold = player.leaderstats.Gold.Value  -- Get players leaderstat values (Gold)
	gems = player.leaderstats.Gems.Value  -- Get players leaderstat values (Gold)
	wood = player.Inventory.Wood.Value  -- Get players leaderstat values (Gold)
	local payload = "UPDATE userData SET gold ='"..gold.."', wood ='"..wood.."', gems='"..gems.."' WHERE userId = '"..player.UserId.."';"  -- Update userData table and set Gold, Wood, Gems where usersId = Players userId
	local response = DataStore3.PostPayload(payload)  -- Send the Post request to the server
end)

Saving Player data every 30 seconds

local DataStore3 = require(game:GetService("ServerScriptService").DataStore3Libary);


local Players = game:GetService("Players")

while true do  -- Infinate Loop
	for i,v in pairs(game.Players:GetChildren()) do  -- Get all active players in game
		local gold = v.leaderstats.Gold.Value  -- Get players Gold Value
		local gems = v.leaderstats.Gems.Value  -- Get players Gems Value
		local wood = v.Inventory.Wood.Value  -- Get players Wood Value
		local payload = "UPDATE userData SET gold ='"..gold.."', wood ='"..wood.."', gems='"..gems.."' WHERE userId = '"..v.UserId.."';" -- Update table called userData and set gold, wood and gems where usersId = players user id
		local response = DataStore3.PostPayload(payload)  -- Send the Post request to the server
	end
	print("Saved Successfully") -- Print to server 'Saved Successfully' only developers will see this as players cant access the server console
	wait(30)  -- Wait 30 seconds to loop again
end