如何实现这个 COUNT(date > NOW()) AS 计数？

Question

我有一张包含现场巡演日期列表的表格，我想每年对它们进行 GROUP，但还要创建一个包含今年剩余日期的新列：

  year   |  count /*of remaining dates*/
  --------------------
  2014   |  12
  2013   |  0
  2012   |  0
  2010   |  0

我试过了，但不起作用：

SELECT YEAR(`date`) AS year, COUNT(`date` > NOW()) AS count
FROM live
GROUP BY YEAR(`date`) 
ORDER BY YEAR(`date`) DESC

Answer 1

试试这个方法

SELECT YEAR(`date`) AS year, SUM(`date` > CURDATE()) AS count
  FROM live
GROUP BY YEAR(`date`) DESC

示例输出：

|年份 |计数 | |--------|--------| | 2013 | 2 | | 2012 | 0 |

这里是SQLFiddle演示