Mysql与PostgreSQL时间问题

PostgreSQL 中的单引号与双引号

PostgreSQL 中的单引号与双引号
在pg中的sql，单引号用来标识实际的值，双引号用来标识表名（table name）或列名（column name）等数据库中存在的值。
如，执行一句query：

select "name" from "students" where "id"='1' 

PostgreSQL的时间问题

使用datetime.datetime.now()插入数据库中的值是东八区时间，例如：2020-04-21 15:24:21.316479+08　　

当前遇到两种情况，配置一样均为RPC：

1、所有时间参数都为东八区，返回的数据也是东八区

import   random
import psycopg2
import  datetime
conn = psycopg2.connect(database="bms", user="bms", password="bms@2018", host="192.168.99.200", port="5432")
cursor=conn.cursor()
began_time = "2020-04-21 14:00:00"
end_time = "2020-04-21 17:00:00"
sql = """
select  bi_aom,timestamp from  tb_2b701b5a704e4e3cb53be00e751bd26d  where timestamp  between  '{}' and  '{}'
""".format(began_time,end_time)
print(sql)
# sql = """
# INSERT INTO "public"."tb_2b701b5a704e4e3cb53be00e751bd26d"("bi_pwr", "ai_frq", "ao_frq", "bo_onf", "bi_onf", "bi_aom", "bi_wfs", "bi_fault", "device_uuid", "timestamp") VALUES (0, NULL, NULL, 0, 0, 1, 0, 0, NULL, '%s');
#
# """%(datetime.datetime.now())
cursor.execute(sql)

data  = cursor.fetchall()
print(data)

2、另一种情况，数据库保存的为东八区时间，但是传入查询时间需要是utc，也就是减去八小时，返回给我时间也是utc则需要加8小时处理

 #传入时间减去八小时
 begin_time = (datetime.datetime.strptime(begin_time, "%Y-%m-%d %H:%M:%S") - datetime.timedelta(hours=8)).strftime("%Y-%m-%d %H:%M:%S")
 end_time = (datetime.datetime.strptime(end_time, "%Y-%m-%d %H:%M:%S")- datetime.timedelta(hours=8)).strftime("%Y-%m-%d %H:%M:%S")
 #查找pg数据
 cursor = connections['timescale'].cursor()
 #pg_sql = "SELECT mean_temperature, to_char(TIMESTAMP, 'YYYY-MM-DD HH24:MI:SS') from {} WHERE TIMESTAMP BETWEEN '{}'  and '{}' ORDER BY TIMESTAMP".format(uuid, begin_time, end_time)
 pg_sql = "SELECT mean_temperature,to_char(TIMESTAMP + '8 hour'  ,'YYYY-MM-DD HH24:MI:SS') from {} WHERE timestamp BETWEEN '{}'  and '{}' ORDER BY TIMESTAMP".format(uuid, begin_time, end_time)
 print(pg_sql)
 cursor.execute(pg_sql)
 result = cursor.fetchall()　　

具体原因未知