mysql - 运行日期/年查询的更有效方法？

我经常使用以下查询，但可以肯定必须有一种更有效的方法来执行此查询。

基本上，我从一个用户表中计算出人们出生的几十年:

select count(*) as howmany, yyyy from bday where (((yyyy > '1949')
AND (yyyy < '1961')) AND (user_id = '63')) UNION
select count(*) as howmany, yyyy from bday where (((yyyy > '1959')
AND (yyyy < '1971')) AND (user_id = '63')) UNION
select count(*) as howmany, yyyy from bday where (((yyyy > '1969')
AND (yyyy < '1981')) AND (user_id = '63')) UNION
select count(*) as howmany, yyyy from bday where (((yyyy > '1979')
AND (yyyy < '1991')) AND (user_id = '63')) UNION
select count(*) as howmany, yyyy from bday where (((yyyy > '1989')
AND (yyyy < '2001')) AND (user_id = '63'))

最佳答案

您可以计算十年并将其用于对用户进行分组:

SELECT
    COUNT(id) AS howmany,
    CEIL((`yyyy`+1)/10) AS decade,
    yyyy
FROM `bday`
GROUP BY decade

关于mysql - 运行日期/年查询的更有效方法？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/10663637/