#709 语言代码

开发者 2021-11-21

语言指包括语言的字符集以及有关的货币符号，日期格式等。为了区分不通的语言，人们设计了一些语言代码相关的标准来。
作为开发，只要涉及多语言，都一定会接触到语言代码。在各种不通的技术、语言框架中，这些代码并没有非常统一，比如简体中文，我见过 zh, zh_CN, zh-Hans, chs, zh_chs 几种不同的表示。

#707 Go 常用库 (持续更新)

Golang 2021-11-21

参考资料与拓展阅读

#706 如何推送消息给手机

开发者 移动端 推送 2021-11-20

我没有做过移动端开发，我突然想到，如果我们要给手机端推送消息，会有些什么办法。
想来想去只有短信是最容易实现的，而且效果可以接受。

#704 常用工具汇总

开发者 开发工具 在线服务 2021-11-18

编辑器

  • VSCode
  • JetBrains 全家桶

SSH

数据库 GUI

Redis GUI

虚拟化与容器

  • VirtualBox
  • Vagrant
  • Docker

编程相关

  • gitg
  • Beyond Compare 可以一直试用
  • Meld Linux 下的简化版 Beyond Compare

其他

在线服务

#702 MySQL 时间相关函数汇总

MySQL 2021-11-16
Name Description
ADDDATE() Add time values (intervals) to a date value
ADDTIME() Add time
CONVERT_TZ() Convert from one time zone to another
CURDATE() Return the current date
CURRENT_DATE(),
CURRENT_DATE		 Synonyms for CURDATE()
CURRENT_TIME(),
CURRENT_TIME		 Synonyms for CURTIME()
CURRENT_TIMESTAMP(),
CURRENT_TIMESTAMP		 Synonyms for NOW()
CURTIME() Return the current time
DATE() Extract the date part of a date or datetime expression
DATE_ADD() Add time values (intervals) to a date value
DATE_FORMAT() Format date as specified
DATE_SUB() Subtract a time value (interval) from a date
DATEDIFF() Subtract two dates
DAY() Synonym for DAYOFMONTH()
DAYNAME() Return the name of the weekday
DAYOFMONTH() Return the day of the month (0-31)
DAYOFWEEK() Return the weekday index of the argument
DAYOFYEAR() Return the day of the year (1-366)
EXTRACT() Extract part of a date
FROM_DAYS() Convert a day number to a date
FROM_UNIXTIME() Format Unix timestamp as a date
GET_FORMAT() Return a date format string
HOUR() Extract the hour
LAST_DAY Return the last day of the month for the argument
LOCALTIME(),
LOCALTIME		 Synonym for NOW()
LOCALTIMESTAMP,
LOCALTIMESTAMP()		 Synonym for NOW()
MAKEDATE() Create a date from the year and day of year
MAKETIME() Create time from hour, minute, second
MICROSECOND() Return the microseconds from argument
MINUTE() Return the minute from the argument
MONTH() Return the month from the date passed
MONTHNAME() Return the name of the month
NOW() Return the current date and time
PERIOD_ADD() Add a period to a year-month
PERIOD_DIFF() Return the number of months between periods
QUARTER() Return the quarter from a date argument
SEC_TO_TIME() Converts seconds to 'hh:mm:ss' format
SECOND() Return the second (0-59)
STR_TO_DATE() Convert a string to a date
SUBDATE() Synonym for DATE_SUB() when invoked with three arguments
SUBTIME() Subtract times
SYSDATE() Return the time at which the function executes
TIME() Extract the time portion of the expression passed
TIME_FORMAT() Format as time
TIME_TO_SEC() Return the argument converted to seconds
TIMEDIFF() Subtract time
TIMESTAMP() With a single argument, this function returns the date or datetime expression;
with two arguments, the sum of the arguments
TIMESTAMPADD() Add an interval to a datetime expression
TIMESTAMPDIFF() Subtract an interval from a datetime expression
TO_DAYS() Return the date argument converted to days
TO_SECONDS() Return the date or datetime argument converted to seconds since Year 0
UNIX_TIMESTAMP() Return a Unix timestamp
UTC_DATE() Return the current UTC date
UTC_TIME() Return the current UTC time
UTC_TIMESTAMP() Return the current UTC date and time
WEEK() Return the week number
WEEKDAY() Return the weekday index
WEEKOFYEAR() Return the calendar week of the date (1-53)
YEAR() Return the year
YEARWEEK() Return the year and week
  • ADDDATE(date, INTERVAL expr unit), ADDDATE(expr, days)
SELECT WEEK(CURRENT_DATE());

SELECT '2021-01-01' AS `Date`, DAYNAME('2021-01-01'), DAYOFWEEK('2021-01-01'), WEEK('2021-01-01'), WEEKDAY('2021-01-01'), WEEKOFYEAR('2021-01-01'), YEARWEEK('2021-01-01')
UNION SELECT '2021-01-06' AS `Date`, DAYNAME('2021-01-04'), DAYOFWEEK('2021-01-04'), WEEK('2021-01-04'), WEEKDAY('2021-01-04'), WEEKOFYEAR('2021-01-04'), YEARWEEK('2021-01-04')
UNION SELECT '2021-01-08' AS `Date`, DAYNAME('2021-01-08'), DAYOFWEEK('2021-01-08'), WEEK('2021-01-08'), WEEKDAY('2021-01-08'), WEEKOFYEAR('2021-01-08'), YEARWEEK('2021-01-08');
-- weekday: monday 0, tuesday 1 ... sunday 6