sqlite3日期数据类型

一、sqlite3日期数据类型，默认用datetime解析（根据stackflow）

使用时注意三点：

　　1. 创建表时，字段 DT 的类型为 date

　　2. 插入数据时，DT字段直接为 str 类型

　　3. DT字段的str ，年月日必须为 xxxx-xx-xx 格式，如 2016-01-01，不能是 2016-1-1

import sqlite3
import datetime

'''sqlite3日期数据类型'''
con = sqlite3.connect(":memory:")
c = con.cursor()

# Create table
c.execute('''CREATE TABLE marksix
            (DT date, Period text, P1 int, P2 int, P3 int, P4 int, P5 int, P6 int, T7 int)''')

# Larger example that inserts many records at a time
purchases = [('2016-01-01', '', 2, 36, 23, 43, 12, 25, 29),
             ('2016-01-03', '', 34, 35, 17, 49, 24, 30, 16),
             ('2016-01-05', '', 1, 35, 12, 49, 49, 26, 34),
             ('2016-01-08', '', 6, 35, 10, 40, 4, 23, 2),
             ('2016-01-10', '', 14, 35, 27, 40, 4, 12, 45),
             ('2016-01-12', '', 33, 10, 13, 21, 27, 22, 17),
             ('2016-01-15', '', 20, 35, 17, 49, 5, 29, 28),
            ]
c.executemany('INSERT INTO marksix (DT,Period,P1,P2,P3,P4,P5,P6,T7) VALUES (?,?,?,?,?,?,?,?,?)', purchases)
for row in c.execute('SELECT * FROM marksix'):
    print(row)

# ==============================================================

# 方式一：显式使用 datetime 类型
t = datetime.datetime.strptime('2016-1-5', '%Y-%m-%d')
dt = (datetime.date(t.year, t.month, t.day), )
for row in c.execute('SELECT * FROM marksix WHERE DT = ?', dt):
    print(row)

# 方式二：直接使用 str 类型
dt = ('2016-01-05', )
for row in c.execute('SELECT * FROM marksix WHERE DT = ?', dt):
    print(row)

#for row in c.execute('SELECT * FROM marksix WHERE dt BETWEEN :begin AND :end;', {"begin": '2016-01-03', "end": '2016-01-11'}):
for row in c.execute('SELECT * FROM marksix WHERE dt BETWEEN ? AND ?;', ('2016-01-03', '2016-01-11')):
    print(row)

二、另一种方式使用时间类型数据（根据官网文档）

import sqlite3
import datetime

# 适配器
def adapt_date(date):
    return datetime.datetime.strftime('%Y/%m/%d', date)
    #return date.strftime('%Y/%m/%d').encode('ascii')
    #return date.strftime('%Y/%m/%d').encode()

# 转换器
def convert_date(string):
    return datetime.datetime.strptime(string.decode(), '%Y/%m/%d')

# 注册适配器
sqlite3.register_adapter(datetime.datetime, adapt_date)

# 注册转换器
sqlite3.register_converter("date", convert_date)

# 注意：detect_types=sqlite3.PARSE_DECLTYPES
con = sqlite3.connect(":memory:", detect_types=sqlite3.PARSE_DECLTYPES)
c = con.cursor()

# Create table
c.execute('''CREATE TABLE marksix
            (dt date, period text, p1 int, p2 int, p3 int, p4 int, p5 int, p6 int, t7 int)''')

# Larger example that inserts many records at a time
purchases = [('2016/1/1', '', 2, 36, 23, 43, 12, 25, 29),
             ('2016/1/3', '', 34, 35, 17, 49, 24, 30, 16),
             ('2016/1/5', '', 1, 35, 12, 49, 49, 26, 34),
             ('2016/1/8', '', 6, 35, 10, 40, 4, 23, 2),
             ('2016/1/10', '', 14, 35, 27, 40, 4, 12, 45),
             ('2016/1/12', '', 33, 10, 13, 21, 27, 22, 17),
             ('2016/1/15', '', 20, 35, 17, 49, 5, 29, 28),
            ]
c.executemany('INSERT INTO marksix VALUES (?,?,?,?,?,?,?,?,?)', purchases)

# Save (commit) the changes
con.commit()

for row in c.execute('SELECT * FROM marksix'):
    print(row)

# ==============================================================

# 显示日期等于2016/1/3的记录
t = ('2016/1/3',)
c.execute('SELECT * FROM marksix WHERE dt = ?', t)
print(c.fetchone())

# 貌似不支持between运算，不知原因！
for row in c.execute('SELECT * FROM marksix WHERE dt BETWEEN ? AND ?;', ('2016/1/3', '2016/1/11')):
    print(row)

三、还有一种日期时间类型：timestamp(时间戳)

import datetime

# Converting SQLite values to custom Python types
# Default adapters and converters for datetime and timestamp
con = sqlite3.connect(":memory:", detect_types=sqlite3.PARSE_DECLTYPES|sqlite3.PARSE_COLNAMES)
cur = con.cursor()

cur.execute('''create table test(
                                d date,
                                ts timestamp
                                )''')

# 插入datetime类型
today = datetime.date.today()
now = datetime.datetime.now()
day1 = datetime.timedelta(days=1)
data = [(today-day1, now-day1),
        (today, now),
        (today+day1, now+day1)]
cur.executemany("insert into test(d, ts) values (?, ?)", data)

# 插入 str 类型
data = [('2016-01-22', '2016-01-22 08:45:50'),
        ('2016-02-22', '2016-02-22 08:45:50'),
        ('2016-03-22', '2016-03-22 08:45:50')]
cur.executemany("insert into test(d, ts) values (?, ?)", data)

for row in cur.execute("select * from test"):
    print(row)

#=================================================================

#begin = datetime.date(2016, 2, 22)
#end = datetime.date(2016, 2, 23)
begin = '2016-02-22'
end = '2016-02-23'
for row in cur.execute("select * from test where d BETWEEN ? AND ?", (begin, end)):
    print(row)

begin = datetime.datetime(2016, 2, 22, 8, 45, 50, 0)
end = datetime.datetime(2016, 2, 23, 20, 10, 47, 12345)
#begin = '2016-02-22 08:45:50'
#end = '2016-02-23 20:10:47'
for row in cur.execute("select * from test where ts BETWEEN ? AND ?", (begin, end)):
    print(row)