【洞库】SQL语句从时间字段中提取年/月

需求
 从register_time中提取年份和月份，并转换成如“2023/01”这种格式。

使用DATE_FORMAT函数。
 并按照“年/月”分组

SELECT 
    DATE_FORMAT(register_time, '%Y/%m') as year_month,
    ROUND(AVG(dry),2) as avgTemperature,
    SUM(CASE WHEN CONVERT(dry,SIGNED) > 30 THEN 1 ELSE 0 END) AS hotDays,
    SUM(CASE WHEN CONVERT(dry,SIGNED) < -12 THEN 1 ELSE 0 END) AS coldDays
FROM
    humiture
WHERE
    is_delete = 0
    AND
    user_cave = '${username}'
    AND
    YEAR(register_time) = YEAR(CURDATE())
GROUP BY DATE_FORMAT(register_time, '%Y/%m');