Question

我的数据库中的项目的时间戳以毫秒为单位

我想从中获取以下项目：

db中项目中每个月的最后一项

我的查询会是什么样的？

Answer 1

如果我明白你想要什么，这就是它的要点。根据需要在选择中添加列。

"SELECT STRFTIME('%m', time) AS month, max(time) FROM test GROUP BY month"

自包含python脚本演示：

from datetime import date
import sqlite3
import random


with open("./test", "w") as f:
    pass

conn = sqlite3.connect("test")
cursor = conn.cursor()

table_sql = "CREATE TABLE test (time TIMESTAMP)"
cursor.execute(table_sql)
conn.commit()

insert_sql = "INSERT INTO test VALUES(?)"
for x in range(100):
    start_date = date.today().replace(day=1, month=1).toordinal()
    end_date = date.today().toordinal()
    random_day = date.fromordinal(random.randint(start_date, end_date))
    cursor.execute(insert_sql, (str(random_day),))
conn.commit()


query = "SELECT STRFTIME('%m', time) AS month, MAX(time) FROM test GROUP BY month"
cursor.execute(query)
print(cursor.fetchall())

信用：Python select random date in current year用于随机日期选择技术。

如何从数据库中获取某些项目

1 个答案: