var stream = require('stream');
var mysql = require('mysql');
var connection = mysql.createConnection({
  host: 'XX',
  user: 'XX',
  password: 'XX',
  database: 'XX'
});

var errList = [];

connection.connect();


connection.query('select id,fans_id,fans_nickname,buyer_id,fans_type,fans_info from yztrade')
  .stream()
  .pipe(stream.Transform({
    objectMode: true,
    transform: function(row, encoding, callback) {
      /**
      if (!!row.fans_id) {
        callback()
      } else {
        /**/
        try {
          var fans = JSON.parse(row.fans_info);
          console.log(fans.fans_id);
          var query = `UPDATE yztrade SET fans_id=${fans.fans_id},fans_nickname='${fans.fans_nickname}',buyer_id=${fans.buyer_id},fans_type=${fans.fans_type} where id=${row.id}`;
          connection.query(query, function(err) {
            if (err) {
              errList.push(row.id);
            }
            console.log(`完成id: ${row.id}`)
            callback();
          });
        } catch (err) {
          errList.push(row.id);
          callback();
        }

      // }
    }
  }))
  .on('finish', function() {
    connection.end();
    if (errList.length) {
      console.log('未正常处理的id为:')
      console.log(errList)
    }
    console.log('end')
  })