SQLite：从日期获取星期数

Question

How can I get week number from date, in SQL there is a function: Datepart(GetDate()) and this return the number of week. How can I get this in SQLite?

Answer 1

You can use the strftime function with the format string (1st parameter) as %W

as per SQL As Understood By SQLite - Date And Time Functions .

Example

DROP TABLE IF EXISTS getweek;
CREATE TABLE IF NOT EXISTS getweek (mydate TEXT);
INSERT INTO getweek VALUES ('2018-01-01'),('2018-02-01'),('2018-03-01');
SELECT *, strftime('%W',mydate) AS weekofyear FROM getweek;

Which results in :-

Note The date has to be in one of the recognised date/time formats (eg 2018/03/01 would result in null as the date is not in recognised format). See the Time Strings section in the link above for the recognised formats.

Answer 2

You can use the appropriate format specifier with strftime() .

See SQLite Date And Time Functions for details.