mysql查询索引,删除索引

#查询表的索引
SHOW INDEX FROM  表名称
#删除表的索引
DROP INDEX STREET ON 表名称(字段);
#实时数据
where dateTime>=(NOW() - interval 24 hour)
#七天的数据
WHERE dateTime >= date_sub(curdate(), interval 7 day)
#当日的日期函数
where date = date_sub(curdate(), interval 2 day)
#
interval是减法的意思

时间的格式,传入开始时间和结束时间,只输入当前日期,规定好后面的时分秒

 WHERE dateTime >= DATE_FORMAT(STR_TO_DATE(#{startTime, jdbcType=VARCHAR}, %Y-%m-%d),%Y-%m-%d 00:00:00) AND dateTime <= DATE_FORMAT(STR_TO_DATE(#{endTime, jdbcType=VARCHAR}, %Y-%m-%d),%Y-%m-%d 23:59:59)
        

case when的用法

SELECT 
    CASE
    WHEN 字段名 = 1 THEN 自住
    WHEN HOUSE_TYPE = 2 THEN 租住
    WHEN HOUSE_TYPE = 3 THEN 投亲靠友
    WHEN HOUSE_TYPE = 4 THEN 酒店
    WHEN HOUSE_TYPE = 5 THEN 民宿
    WHEN HOUSE_TYPE = 6 THEN 宿舍
    WHEN HOUSE_TYPE = 7 THEN 工棚
    WHEN HOUSE_TYPE = 8 THEN 其他
    END as `name`,
    count(1) `value`
    FROM
    t_dws_dt_yd_tianfu_healthy_communication
    WHERE STREET = 条件
    GROUP BY name

另外一种写法

SELECT
    CASE
    WHEN HOUSE_TYPE = 1 THEN 自住
    WHEN HOUSE_TYPE = 2 THEN 租住
    WHEN HOUSE_TYPE = 3 THEN 投亲靠友
    WHEN HOUSE_TYPE = 4 THEN 酒店
    WHEN HOUSE_TYPE = 5 THEN 民宿
    WHEN HOUSE_TYPE = 6 THEN 宿舍
    WHEN HOUSE_TYPE = 7 THEN 工棚
    else 其他
    END as name,
    count(1) value
    FROM
    t_dws_dt_yd_tianfu_healthy_communication
    WHERE STREET = #{street}
    GROUP BY name
    ORDER BY value DESC

 

mysql查询索引,删除索引

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