Question

Having a following table:

CREATE TABLE `foo`(
  `year` INT NOT NULL,
  `month` INT NOT NULL,
  `day` INT NOT NULL,
  `hour` INT NOT NULL,
  `minute` INT NOT NULL,
  `value` INT NOT NULL,
  PRIMARY KEY(`year`, `month`, `day`, `hour`, `minute`)
);

How to select all the Monday records in SQLite?

Answer 1

1. convert the date into a format understood by SQLite, which requires padding with zeros to the required four/two digit field width to get YYYY-MM-DD;
2. then just use strftime('%w') to get the week day:

SELECT *
FROM foo
WHERE strftime('%w',
               substr('000' || year,  -4) || '-' ||
               substr('0'   || month, -2) || '-' ||
               substr('0'   || day,   -2)           ) = '1'