oracle統計一年中每個月的資料

第一種寫法： 

SELECT SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 1, B.PRICE, 0)) AS A,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 2, B.PRICE, 0)) AS B,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 3, B.PRICE, 0)) AS C,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 4, B.PRICE, 0)) AS D,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 5, B.PRICE, 0)) AS E,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 6, B.PRICE, 0)) AS F,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 7, B.PRICE, 0)) AS G,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 8, B.PRICE, 0)) AS H,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 9, B.PRICE, 0)) AS I,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 10, B.PRICE, 0)) AS J,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 11, B.PRICE, 0)) AS K,
       SUM(DECODE(EXTRACT(MONTH FROM B.TIMES), 12, B.PRICE, 0)) AS L
  FROM PAY B
 WHERE USERID = 1
   AND EXTRACT(YEAR FROM B.TIMES) = '2012'
           

加一種寫法：

SELECT SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '01', B.PRICE, 0)) M1,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '02', B.PRICE, 0)) M2,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '03', B.PRICE, 0)) M3,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '04', B.PRICE, 0)) M4,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '05', B.PRICE, 0)) M5,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '06', B.PRICE, 0)) M6,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '07', B.PRICE, 0)) M7,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '08', B.PRICE, 0)) M8,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '09', B.PRICE, 0)) M9,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '10', B.PRICE, 0)) M10,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '11', B.PRICE, 0)) M11,
       SUM(DECODE(TO_CHAR(B.TIMES, 'MM'), '12', B.PRICE, 0)) M12
  FROM PAY B
 WHERE USERID = 1
   AND TO_CHAR(B.TIMES, 'yyyy') = '2012'