import pymysql

class MK_sql ():

"""

构建mySQL常见语句：增删改查排序

"""

def __init__(self, table_name):

self.table_name = table_name

def mk_create(self, value: list):

"""

构建mySQL创建表语句

@param value: 字段列表

@return:

"""

if not isinstance (value, list):

raise Exception ("TypeError")

sql = "create table %s (%s)" % (self.table_name, self.to_str (value))

return sql

def mk_delete(self, condition: dict):

"""

构建mySQL删除指定字段语句

@param condition: 删除条件，dict型

@return:

"""

if not isinstance (condition, dict):

raise Exception ("TypeError")

sql = "delete from %s" % self.table_name

sql += " where %s " % self.to_str_and (condition)

return sql

def mk_insert(self, value: list):

"""

构建mySQL插入字段语句

@param value: 需插入的整行数据

@return:

"""

if not isinstance (value, list):

raise Exception ("TypeError")

sql = "insert into %s values " % self.table_name

sql += str (value)

return sql

def mk_update(self, value: dict, condition: dict):

"""

构建mySQL更新字段语句

@param value: dict 要更新的字段

@param condition: dict SQL条件语句

@return:

"""

if not isinstance (value, dict) or not isinstance (condition, dict):

raise Exception ("TypeError")

sql = "update %s set " % self.table_name

sql += self.to_str (value)

sql += " where %s " % self.to_str_and (condition)

return sql

def mk_select(self, cols=None, limit=None, distinct=False):

"""

构建mySQL select查询语句

@param cols: list型，要查询的字段名称

@param limit: int型

@param distinct: bool型，True:去重，只作用于非全部查询

@return:

"""

if (cols != None and not isinstance (cols, list)) or \

(limit !=None and not isinstance (limit, int)) or not isinstance(distinct,bool):

raise Exception ("TypeError")

if not limit:

if not cols:

sql = "select * from %s" % self.table_name

else:

if not distinct:

sql = "select %s from %s" % (self.to_str (cols), self.table_name)

else:

sql = "select distinct %s from %s" % (self.to_str (cols), self.table_name)

return sql

else:

if not isinstance (limit, int):

raise Exception ("TypeError")

if not cols:

sql = "select * from %s limit %s" % (self.table_name, limit)

else:

if not distinct:

sql = "select %s from %s limit %s" % (self.to_str (cols), self.table_name, limit)

else:

sql = "select distinct %s from %s limit %s" % (self.to_str (cols), self.table_name, limit)

return sql

def mk_order_by(self, value: list, asc=True):

"""

构建mySQL排序语句

@param value: 单个字段或多个字段

@param asc: 默认为True升序，FALSE为降序

@return:

"""

if not isinstance (value, list) or not isinstance(asc,bool):

raise Exception ("TypeError")

if asc:

sql = "order by %s from %s" % (self.to_str (value), self.table_name)

else:

sql = "order by %s from %s desc" % (self.to_str (value), self.table_name)

return sql

def to_str_and(self, value: dict):

"""

内部函数，用于转换mySQL带and条件语句

@param value:dict型

@return: [key='value' and key='value' and...]

"""

info_list = ["%s='%s'" % (str (k), str (v)) for k, v in value.items ()]

return " and ".join (info_list)

def to_str(self, value):

"""

内部函数，转换成SQL指定的str格式

@param value: list/dict

@return: 1、list参数不带引号的str，2、dict参数返回[key='value', key='value'...]

"""

if isinstance (value, list):

cnt = ["%s" % value for value in value]

return ",".join ((cnt))

elif isinstance (value, dict):

cnt = ["%s='%s'" % (str (k), str (v)) for k, v in value.items ()]

return ",".join (cnt)