个人sql代码规范书写_仅供参考

版权声明：希望能和看到文章的你交个朋友 https://blog.csdn.net/u012954706/article/details/85053594

1、left join

on 后面的写前面的字段，这样个人认为比较好区分

1、没有子查询的时候

select o.createTime,
       o.clickTime,
       c.itemTitle,
       o.itemId,
       o.orderNo,
       c.shopTitle,
       o.estimateAmount,
       o.payAmount,
       c.commissionRatio,
       o.orderStatus
from user_order        o   left  join
     coupon_taoke_data c       on      c.id = o.taokeId
where 1=1

2、有子查询

 select  o.payAmount,
          o.estimateAmount,
       ( IFNULL(o3.notValidOrderSize ,0 ) + IFNULL(o.orderSize ,0 ) ) as orderSize
from user_info u  left join  (select    IFNULL(count(o1.orderNo),0 )  as orderSize ,
                                        IFNULL(sum(o1.estimateAmount) ,0)  as  estimateAmount ,
                                        IFNULL(sum(o1.payAmount) ,0) as payAmount,
                                        o1.userInfoId as userInfoId
                                from    user_order o1
                                where   o1.userInfoId = 4 and o1.orderStatus !='订单失效'
                             )
          o on o.userInfoId = u.id
                  left join   (select IFNULL(count(o2.orderNo),0 ) as notValidOrderSize,
                                        o2.userInfoId as userInfoId
                                 from   user_order o2
                                 where o2.orderStatus ='订单失效'  and o2.userInfoId = 4
                              )
         o3 on o3.userInfoId = u.id
where u.id = 4;
   
        

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