mybatis之sql问题清单

mysql之sql问题清单

sql执行顺序

书写sql的顺序是

select
from
join on
where
group by
having
order by
limit

mysql执行sql的顺序为

from
join on
where
group by
having
select
order by
limit

mysql创建复杂一点的计算列

CREATE TABLE log_sync_plan_data(
    planLogId BIGINT PRIMARY KEY NOT NULL auto_increment,
    syncType int NOT NULL DEFAULT 0,
    tablesCnt int NOT NULL,
    finishedCnt int NOT NULL DEFAULT 0,
    test decimal(10,2) GENERATED ALWAYS AS ((`syncType ` * `tablesCnt `)) VIRTUAL
    -- test DECIMAL(18,4) generated always AS (syncType *tablesCnt )
    beginTime datetime NOT NULL DEFAULT NOW(),
    endTime datetime NOT NULL DEFAULT '1900-01-01',
    elapsedSeconds INT generated always AS (case when endTime<beginTime then -1 ELSE timestampdiff(SECOND,endTime,beginTime) END) VIRTUAL,
    errMsg varchar(4000) NULL,
    success INT generated always AS( case when endTime<beginTime OR ifnull(errMsg,'')<>'' OR tablesCnt<>finishedCnt then 0 else 1 end) VIRTUAL
);

mysql5.7后查询多个列+group by就会报sql_mode=only_full_group_by错误

SELECT 要查询的所有字段列表没有包含在 GROUP BY 语句中

SQL 日期函数

1. DATE_FORMAT() 函数格式化时间

https://www.w3school.com.cn/sql/func_date_format.asp

2. datediff（）函数计算时间差

https://www.w3school.com.cn/sql/func_datediff_mysql.asp

多条件分组统计

SELECT date_format((time),'%Y.%m') as timeGroup,count(id),emotion from yuqing_option_info
    WHERE time BETWEEN '2018-08-08' and '2019-08-08'  GROUP BY timeGroup,emotion

在这里插入图片描述

 SELECT date_format((OD_CREATETIME),'%m-%d') as days,sum(odi_num) as nums,sum(sp_selling_price) as prices FROM (SELECT OD_CREATETIME,odi_num,sp_selling_price from (


          select OD_CREATETIME,odi_num,sp_selling_price

          from sys_order,sys_order_item,sys_supplies

          where sys_order_item.OD_ID=sys_order.ID

          AND sys_supplies.ID=sys_order_item.SP_ID

          AND sys_order.OD_TYPE=#{orderType}

          and sys_order.O_ID=#{hId}

          and sys_order.OD_CREATETIME   BETWEEN #{startTime} and #{endTime}

          ) as d ) as c

          GROUP BY days

SELECT sum(i.ODI_NUM * s.SP_SELLING_PRICE) AS number,
               DATE(o.OD_CREATETIME) AS time
        FROM sys_order_item i
        LEFT JOIN sys_order o on o.ID=i.OD_ID
        LEFT JOIN sys_hospital h on o.F_O_ID=h.ID
        LEFT JOIN sys_supplies s on i.SP_ID=s.ID
        WHERE o.OD_TYPE =#{orderType}
        GROUP BY DATE(o.OD_CREATETIME)
        ORDER BY DATE(o.OD_CREATETIME) DESC
        LIMIT 30

//模糊查询
@Query(nativeQuery = true,value = “select s.name name,sa.expiring_time expiringTime from subject s\n” +
" inner JOIN subject_auths sa ON sa.subject_id=s.id \n" +
" inner JOIN subject_favorites sf ON sf.subject_auths_id=sa.id\n" +
" where sa.user_id=?1 and (s.bond_code like CONCAT(’%’,?2,’%’) or s.wind_code like CONCAT(’%’,?2,’%’) OR s.name like CONCAT(’%’,?2,’%’) ) “,countQuery = “select count(*) expiringTime from subject s\n” +
" inner JOIN subject_auths sa ON sa.subject_id=s.id \n” +
" inner JOIN subject_favorites sf ON sf.subject_auths_id=sa.id\n" +
" where sa.user_id=?1 and (s.comp_bode like CONCAT(’%’,?2,’%’) or s.wind_code like CONCAT(’%’,?2,’%’) OR s.name like CONCAT(’%’,?2,’%’) ) "
)