请帮助使用以下代码。我无法在 selectCb 函数中返回“结果”变量。“结果”已分配并在 selectCb 范围内正常工作,但在范围之外我无法访问它。
function queryDB(client,queryString) {
result = ''; //declare global variable
client.query(queryString, function selectCb(error, results, fields) {
if (results.length > 0) result = results[0];
console.log(result['id']); //WORKS HERE
});
client.end();
console.log(result['id']); //DOES NOT WORK - UNDEFINED
return result; //return result array
};
var data = queryDB(client,"select id from table");
console.log(data['id']) //DOES NOT WORK - UNDEFINED;