Day of the week: Difference between revisions
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=={{header|SQL}}==
=={{header|Oracle}}==
SQL has good support for date functions; care must be taken with NLS settings (globalization support), in the code below the date format language is passed in as an argument to the relevant function. (Or, see a variation that does not depend on language settings, after the output shown below.)
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Alternatively, the WHERE clause can be written in a way that avoids the complication of language settings. The (overloaded) TRUNC function, as applied to dates, takes a second argument indicating "to what" we must truncate. One option is 'iw' for "ISO week"; this truncates to the most recent Monday (the beginning of the ISO standard week, which is Monday through Sunday by definition). Like so (replace in the query above):
<syntaxhighlight lang="sql">where dt - trunc(dt, 'iw') = 6</syntaxhighlight>
=={{header|SQLite3}}==
<syntaxhighlight lang="sql">WITH RECURSIVE cte AS (
SELECT DATE('2008-12-25', '+'||(12*0)||' months') as dt, 1 AS level
UNION ALL
SELECT DATE('2008-12-25', '+'||(12*level)||' months') as dt, c.level + 1
FROM cte c
WHERE c.level <= 2121 - 2008 + 1
)
SELECT strftime('%Y', dt)
FROM cte
where strftime('%w', dt) = '0';
</syntaxhighlight>
=={{header|PostgreSQL}}==
<syntaxhighlight lang="sql"> WITH RECURSIVE cte AS (
SELECT date '2008-12-25' + interval '12 month' * 0 as dt, 1 AS level
UNION ALL
SELECT date '2008-12-25' + interval '12 month' * level as dt, c.level + 1
FROM cte c
WHERE c.level <= 2121 - 2008 + 1
)
SELECT dt
FROM cte
where to_char(dt, 'Dy') = 'Sun';
</syntaxhighlight>
=={{header|Standard ML}}==
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