SQLite3日期与时间，常见函数

sqlite3 #con = sqlite3.connect(‘example.db‘) con = sqlite3.connect(":memory:") c = con.cursor() # Create table c.execute(‘‘‘CREATE TABLE stocks (date text, trans text, symbol text, qty real, price real)‘‘‘) # Insert a row of data c.execute("INSERT INTO stocks VALUES (?,?,?,?,?)", (‘2006-03-27‘,‘BUY‘,‘RHAT‘,100,60.14)) # Larger example that inserts many records at a time purchases = [(‘2006-03-28‘, ‘BUY‘, ‘IBM‘, 1000, 45.00), (‘2006-04-05‘, ‘BUY‘, ‘MSFT‘, 1000, 72.00), (‘2006-04-06‘, ‘SELL‘, ‘IBM‘, 500, 53.00), (‘2006-04-07‘, ‘SELL‘, ‘MSFT‘, 500, 74.00), (‘2006-04-08‘, ‘SELL‘, ‘IBM‘, 500, 54.00), (‘2006-04-09‘, ‘SELL‘, ‘MSFT‘, 500, 73.00), (‘2006-04-10‘, ‘SELL‘, ‘MSFT‘, 500, 75.00), (‘2006-04-12‘, ‘SELL‘, ‘IBM‘, 500, 55.00), ] c.executemany(‘INSERT INTO stocks VALUES (?,?,?,?,?)‘, purchases) # Save (commit) the changes con.commit() # Do this instead t = (‘RHAT‘,) c.execute(‘SELECT * FROM stocks WHERE symbol=?‘, t) #print(c.fetchone()) #for row in c.execute(‘SELECT * FROM stocks ORDER BY price‘): # print(row) #for row in c.execute(‘SELECT * FROM stocks LIMIT 5 OFFSET 0‘): # print(row) for row in c.execute(‘SELECT * FROM stocks LIMIT 5 OFFSET 1‘): print(row) #Select Top N * From # ==================================================================================== # SQLite 日期 & 时间 # ==================================================================================== print(‘=‘*30) print(‘SQLite 日期 & 时间‘) print(‘=‘*30) # 计算当前日期 c.execute("SELECT date(‘now‘)") print(c.fetchone()) # 计算当前月份的最后一天： c.execute("SELECT date(‘now‘,‘start of month‘,‘+1 month‘,‘-1 day‘);") print(c.fetchone()) # 计算给定 UNIX 时间戳 1092941466 的日期和时间： c.execute("SELECT datetime(1092941466, ‘unixepoch‘);") print(c.fetchone()) # 计算给定 UNIX 时间戳 1092941466 相对本地时区的日期和时间： c.execute("SELECT datetime(1092941466, ‘unixepoch‘, ‘localtime‘);") print(c.fetchone()) # 计算当前的 UNIX 时间戳： c.execute("SELECT datetime(1092941466, ‘unixepoch‘, ‘localtime‘);") print(c.fetchone()) # 计算美国"独立宣言"签署以来的天数： c.execute("SELECT julianday(‘now‘) - julianday(‘1776-07-04‘);") print(c.fetchone()) # 计算从 2004 年某一特定时刻以来的秒数： c.execute("SELECT strftime(‘%s‘,‘now‘) - strftime(‘%s‘,‘2004-01-01 02:34:56‘);") print(c.fetchone()) # 计算当年 10 月的第一个星期二的日期： c.execute("SELECT date(‘now‘,‘start of year‘,‘+9 months‘,‘weekday 2‘);") print(c.fetchone()) # 计算从 UNIX 纪元算起的以秒为单位的时间（类似 strftime(‘%s‘,‘now‘) ，不同的是这里有包括小数部分）： c.execute("SELECT (julianday(‘now‘) - 2440587.5)*86400.0;") print(c.fetchone()) # 在 UTC 与本地时间值之间进行转换，当格式化日期时，使用 utc 或 localtime 修饰符，如下所示： c.execute("SELECT time(‘12:00‘, ‘localtime‘);") print(c.fetchone()) # c.execute("SELECT time(‘12:00‘, ‘utc‘);") print(c.fetchone()) con.close() # ==================================================================================== # SQLite 常用函数 # ==================================================================================== print(‘=‘*30) print(‘SQLite 常用函数‘) print(‘=‘*30) con = sqlite3.connect(":memory:") c = con.cursor() # Create table c.execute(‘‘‘CREATE TABLE COMPANY (ID integer, NAME text, AGE integer, ADDRESS text, SALARY real)‘‘‘) # Larger example that inserts many records at a time purchases = [(1,‘Paul‘,32,‘California‘,20000.0), (2,‘Allen‘,25,‘Texas‘,15000.0), (3,‘Teddy‘,23,‘Norway‘,20000.0), (4,‘Mark‘,25,‘Rich-Mond‘,65000.0), (5,‘David‘,27,‘Texas‘,85000.0), (6,‘Kim‘,22,‘South-Hall‘,45000.0), (7,‘James‘,24,‘Houston‘,10000.0)] c.executemany(‘INSERT INTO COMPANY VALUES (?,?,?,?,?)‘, purchases) # Save (commit) the changes con.commit()
# 返回数据库表最后 n 行记录 # 先计算一个数据库表中的行数 c.execute("SELECT count(*) FROM COMPANY;") last = c.fetchone()[0] n = 5 c.execute("SELECT * FROM COMPANY LIMIT ? OFFSET ?;", (n, last-n)) for row in c: print(row)

# 计算一个数据库表中的行数 c.execute("SELECT count(*) FROM COMPANY;") print(c.fetchone()) # 选择某列的最大值 c.execute("SELECT max(salary) FROM COMPANY;") print(c.fetchone()) # 选择某列的最小值 c.execute("SELECT min(salary) FROM COMPANY;") print(c.fetchone()) # 计算某列的平均值 c.execute("SELECT avg(salary) FROM COMPANY;") print(c.fetchone()) # 为一个数值列计算总和 c.execute("SELECT sum(salary) FROM COMPANY;") print(c.fetchone()) # 返回一个介于 -9223372036854775808 和 +9223372036854775807 之间的伪随机整数 c.execute("SELECT random() AS Random;") print(c.fetchone()) # 返回数值参数的绝对值 c.execute("SELECT abs(5), abs(-15), abs(NULL), abs(0), abs(‘ABC‘);") print(c.fetchone()) # 把字符串转换为大写字母 c.execute("SELECT upper(name) FROM COMPANY;") print(c.fetchone()) # 把字符串转换为小写字母 c.execute("SELECT lower(name) FROM COMPANY;") print(c.fetchone()) # 返回字符串的长度 c.execute("SELECT name, length(name) FROM COMPANY;") print(c.fetchone()) # 返回 SQLite 库的版本 c.execute("SELECT sqlite_version() AS ‘SQLite Version‘;") print(c.fetchone()) # c.execute("SELECT CURRENT_TIMESTAMP;") print(c.fetchone())

 

SQLite3日期与时间，常见函数

标签：