Comparing only Year and Month

问题

I'm using this to compare Year and month, but it failing when month is less than current month even though the year is greater than current year

SELECT * FROM DUMMY_TABLE WHERE
YEAR(PREV_ELIG_REV_DT) >= YEAR(CURRENT TIMESTAMP)
AND MONTH(PREV_ELIG_REV_DT) >= MONTH(CURRENT TIMESTAMP)

回答1:

You could add and extra condition to match the situation when the YEAR is equal..

SELECT * 
  FROM DUMMY_TABLE 
  WHERE
     YEAR(PREV_ELIG_REV_DT) > YEAR(CURRENT TIMESTAMP)
  OR (    YEAR(PREV_ELIG_REV_DT) = YEAR(CURRENT TIMESTAMP)
     AND MONTH(PREV_ELIG_REV_DT) >= MONTH(CURRENT TIMESTAMP))

UPDATE

As @Clockwork-Muse said, an alternative approach that may yield better performance would be to get the beginning of the current month and compare against that:

SELECT * 
  FROM DUMMY_TABLE 
  WHERE
     PREV_ELIG_REV_DT >= (CURRENT DATE - (DAY(CURRENT DATE)-1) DAYS)

回答2:

try this

SELECT * FROM DUMMY_TABLE 
WHERE
     YEAR(PREV_ELIG_REV_DT)*100 + MONTH(PREV_ELIG_REV_DT) 
  >= YEAR(CURRENT TIMESTAMP) * 100 + MONTH(CURRENT TIMESTAMP)

来源：https://stackoverflow.com/questions/22414360/comparing-only-year-and-month