Python将数据库中数据导出为csv文件

1、这里使用PyQt5中内置数据库连接mysql方法

    self.db = QSqlDatabase.addDatabase('QMYSQL')  # 数据库设置
        self.db.setHostName('localhost')
        self.db.setDatabaseName('bigpeng')
        self.db.setUserName('root')
        self.db.setPassword('')
        if not self.db.open():
            QMessageBox.critical(None, ('无法打开数据库'), ('无法建立连接，需要配置'), QMessageBox.Cancel)
            return False
        query = QSqlQuery()
        query.exec("select * from df_grounddata where tu_place='大棚一'")
        filename = 'data.csv'# 导出为csv文件
        with open(filename, mode='w', encoding='utf-8') as f:
            write = csv.writer(f, dialect='excel')
            write.writerow(['时间', '位置','土壤深度','温度', '湿度'])# 先写下标题
            while query.next():
                date = query.value(1).toString('yyyy-MM-dd HH:mm:ss')
                place = query.value(4)
                depth = query.value(5)
                shidu = query.value(6)
                wendu = query.value(7)
                write.writerow([date,place,depth,shidu,wendu])# 每次写一行

2、使用Python连接数据库mysql方法

import pymysql
import csv

def from_mysql_get_all_info():
    conn = pymysql.connect(
        host='xxxxxx',
        port=3306,
        user='xxxx',
        db=xx',
        password='xxxxx',
        charset='utf8mb4'
    cursor = conn.cursor()
    sql = 'select * from py.tencent_news'
    cursor.execute(sql.encode('utf-8'))
    data = cursor.fetchall()
    conn.close()
    return data


def write_csv():
    data = from_mysql_get_all_info()
    filename = 'data/corpus.csv'#文件名和路径
    with open(filename,mode='w',encoding='utf-8') as f:
        write = csv.writer(f,dialect='excel')
        for item in data:
            write.writerow(item)

write_csv()