QUARTER

QUARTER allows you to retrieve the 3 month period from a date.

   QUARTER(d)

In this example you get the quarter from the date field wk. Lately, Cliff Richard favours Q4.

SELECT wk,
       EXTRACT(QUARTER from wk) AS Quarter,
       song
  FROM totp
 WHERE singer = 'Cliff Richard'
 ORDER BY wk DESC

SELECT wk,
       TO_CHAR(wk,'QUARTER') AS Quarter,
       song
  FROM gisq.totp
 WHERE singer = 'Cliff Richard'
 ORDER BY wk DESC

SELECT wk,
       DATEPART(QUARTER,wk) AS Quarter,
       song
  FROM totp
 WHERE singer = 'Cliff Richard'
 ORDER BY wk DESC

SELECT wk,
       QUARTER(wk) AS Quarter,
       song
  FROM totp
 WHERE singer = 'Cliff Richard'
 ORDER BY wk DESC