main.lua

local libmysql = require("libmysql")
local db_member = libmysql:new("member")
local db_test = libmysql:new()

local res, err =  db_member:query("select des from test1 where (test_id=? )", {3})
if err or not res or type(res)~="table" or #res<1 then
   ngx.say("test database member query :nothing") 
else
    ngx.say("test database member query :res") 
end

local res, err =  db_test:query("select des from test1 where test_id=? ;", {3})
if err or not res or type(res)~="table" or #res<1 then
   ngx.say("test database test query :nothing") 
else
    ngx.say("test database test query :res") 
end
local res, err =  db_test:main("UPDATE test1 SET des='my lua' WHERE test_id=?", {3})