function addMethod(object, name, fn) {　　var old = object[name];　　object[name] = function() {　　　　if(fn.length === Object.getOwnPropertyNames(arguments[0]).length) {　　　　　　return fn.apply(this, arguments);　　　　} else if(typeof old === "function") {　　　　　　return old.apply(this, arguments);　　　　}//Object.getOwnPropertyNames(arguments[0]).length　　}}var SQL={};addMethod(SQL, "select", function(table,a) {　　var ret = [];//table,join,where　　for (var Key in table.where){		console.log(Key+"="+this.values[2][Key]);	}　　return ret;});addMethod(SQL, "select", function(table,a,b) {　　var ret = [];		for(var tab in table.joinl)	{		ret.push(table.joinl[tab]);	}	var sql="SELECT "+ret.join(",")+" FROM "+table.table;　　return sql;}); var people = {	table:"表名",	joinl:["字段1","字段2","字段3"],	where: {			"user_id[=]":"foo",			"user_id[>]":1000,			"user_id[<]":500,			"user_id[!=]":"foo"		}};console.log(SQL.select(people));