脳ログ

• 今日が今月の第n週目かを返す
• 引数:なし
• 戻値:int

CREATE OR REPLACE FUNCTION nweek() RETURNS integer AS $$ SELECT CASE WHEN date_trunc('month',now() - interval '7 day') = date_trunc('month',now() - interval '1 month') THEN 1 WHEN date_trunc('month',now() - interval '14 day') = date_trunc('month',now() - interval '1 month') THEN 2 WHEN date_trunc('month',now() - interval '21 day') = date_trunc('month',now() - interval '1 month') THEN 3 WHEN date_trunc('month',now() - interval '28 day') = date_trunc('month',now() - interval '1 month') THEN 4 ELSE 5 END ; $$ LANGUAGE SQL ;