我在用node查询数据库中使用如下代码：
var _password =mysql.query(table," where name = " + "'" + name + "'","password");
其中mysql.query为
query(table,others,column){
var connection = this.connection;
var sql;
if(column) sql = "select " + column + " from " + table;
else{sql = "select * from " + table;}
if(others) sql += " " + others;
console.log(sql);
var result;
connection.query(sql,function(err,rows,fields){
if(err){
throw err;
}
if(rows.length > 1){
rows.forEach(function(row){
console.log(row);
});
}
else if(rows.length == 1){
console.log(rows[0]);
rows = rows[0];
}
else{
console.log("没有数据");
}
return rows;
});
console.log('result:');
console.log(result);
return result;
}
最终的结果是：
很显然query之后的语句先执行了，此处无法使用yield，请大神指教
天蓬老师2017-04-17 16:34:45
rows.forEach(function(row){
console.log(row);
});这里面的循环是异步的，所以出问题了，你要控制住异步。
给你一个例子，我刚学着写，应该写的不咋地，但是可以给你演示如何控制异步。
这里是引用的cc这个model里的，不写全了，大概看一下
getGrades: async () => {
return new Promise((resolve, reject) => {
db.pool.query('SELECT * FROM set_grades', function (err, rows) {
if(rows){
resolve(rows);
}
else{
console.log(err);
reject(err);
}
});
});
},
getTerms: async (grade_id) => {
return new Promise((resolve, reject) => {
db.pool.query('SELECT * FROM set_terms WHERE grade_id = ?', grade_id,function (err, rows) {
if(rows){
resolve(rows);
}
else{
console.log(err);
reject(err);
}
});
});
},
// ------------创建合同-------------
exports.createContract = async (ctx, next)=> {
// 1 获取types
let types = new Array();
await cc.getTypes().then(result => {
types = result;
});
// 2 获取cats
let cats = new Array();
await cc.getCats().then(result => {
cats = result;
});
// 3 获取grades
let grades = new Array();
await cc.getGrades().then(result => {
grades = result;
});
// 4 获取terms
// 遍历每一个grades，然后获取下面的terms，合并到grades
let forGrades = async function(grades) {
for(let grade of grades){
await cc.getTerms(grade.grade_id).then(result => {
grade.terms = result;
});
}
}
await forGrades(grades);
await ctx.render('cc/createContract',{
title: 'Create Contract',
student_id: ctx.params.id,
types: types,
cats: cats,
grades: grades
})
}