问如何比较甲骨文11g中的月份和日的值，并在where子句中使用它？

EN

CREATE TABLE table1 (
  month NUMBER(2,0),
  day   NUMBER(2,0),
  value VARCHAR2(4000)
);

INSERT INTO table1
  SELECT EXTRACT( MONTH FROM date_column ),
         EXTRACT( DAY   FROM date_column ),
         value
  FROM   table2;

SELECT month, d1, d2, d3, d4, /* ..., */ d31
FROM   table1
PIVOT  ( MAX( value ) FOR day IN (
           1 AS d1, 2 AS d2, 3 As d3, 4 AS d4, /* ..., */ 31 AS d31
       ) );

INSERT INTO table1
  SELECT month, d1, d2, /* ..., */ d31
  FROM   ( SELECT EXTRACT( MONTH FROM date_column ) AS month,
                  EXTRACT( DAY   FROM date_column ) AS day,
                  value
           FROM   table2 )
  PIVOT  ( MAX( value ) FOR day IN (
             1 AS d1, 2 AS d2, /* ..., */ 31 AS d31
         ) );