格式化日期字段为年月日格式：
DATE_FORMAT(create_time, '%Y%m%d')
通过日期查询对应的日期的总数：
SELECT
DATE_FORMAT(create_time, '%Y%m%d') date,
count(*) count
FROM
system
GROUP BY
DATE_FORMAT(create_time, '%Y%m%d');
count 的条件查询
查询type字段为SOURCE_SEARCH 的count
count(type= 'SOURCE_SEARCH' OR NULL)
count(type= 'TYPE' and type2 = 'TYPE2' OR NULL)
通过日期分组查询条件下的count
SELECT
DATE_FORMAT(create_time, '%Y%m%d') date,
count(type= 'TYPE' OR NULL) count
FROM
system
GROUP BY
DATE_FORMAT(create_time, '%Y%m%d');
