MySQL convert YEARWEEK to date

问题:

I've a YEARWEEK() converted value from MySQL

201439 

I want to convert it back to the starting date of that week number, using MySQL, possible?

e.g.

SELECT xxx('201439'); 

and return

'2014-09-16' 

回答1:

You can use STR_TO_DATE function with format you need

http://sqlfiddle.com/#!9/9eecb7d/2017

SELECT STR_TO_DATE(CONCAT(YEARWEEK(NOW()),' Monday'), '%X%V %W');  SELECT STR_TO_DATE(CONCAT('201439',' Monday'), '%X%V %W'); 

回答2:

You need to be careful that the yearweek is in the expected "mode". (See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_week)

The formatting used in the STR_TO_DATE should match. (See https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_date-format)

e.g. If using mode 2 (1-53, Week 1 is the first week with a Sunday in it, weeks start on a Sunday)

SELECT STR_TO_DATE(CONCAT('201439',' Sunday'), '%X%V %W'); 

e.g. If using mode 3 (following ISO-8601), (1-53, Week 1 is the first week with 4 or more days, starting on a Monday), you need to use the lower-case version.

SELECT STR_TO_DATE(CONCAT('201439',' Monday'), '%x%v %W'); 

So, one would get the following (2014-09-28 is a Sunday):

SELECT yearweek('2014-09-28', 2); 201439 SELECT yearweek('2014-09-28', 3); 201439 SELECT yearweek('2014-09-29', 2); 201439 SELECT yearweek('2014-09-29', 3); 201440 

then

SELECT STR_TO_DATE(CONCAT('201439',' Sunday'), '%X%V %W'); -- mode 2 2014-09-28 SELECT STR_TO_DATE(CONCAT('201439',' Monday'), '%x%v %W'); -- mode 3  2014-09-22 SELECT STR_TO_DATE(CONCAT('201440',' Monday'), '%x%v %W'); -- mode 3 2014-09-29 

回答3:

Try:

SELECT DATE(CONCAT(LEFT('201439', 4), '-01-01')) + INTERVAL RIGHT('201439', 2)-1 WEEK 

This won't get the beginning of the week, it will get the same day of the week as January 1 of that year.

回答4:

You can use this code likes example:

String string = "January 2, 2010"; DateFormat format = new SimpleDateFormat("MMMM d, yyyy", Locale.ENGLISH); Date date = format.parse(string); 

Hope you like it! ^^

文章来源: MySQL convert YEARWEEK to date