对比Excel的10个功能，学习SQL好像也快了？

create table sale_guang SELECT * from sale where city="广州";

SELECT * from sale ainner JOIN(SELECT ordernum,profit from sale_guang) b style="margin: -0.8em 0px; color: rgb(26, 26, 26); font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", "Noto Sans CJK SC", "WenQuanYi Micro Hei", sans-serif; font-size: medium;              background-color: rgb(255, 255, 255);  ">

SELECT * from sale aWHERE a.ordernum not in (SELECT b.ordernum from sale_guang b);

SELECT * FROM salewhere salesnum not in (SELECT salesnum from sale GROUP BY salesman HAVING COUNT(salesnum)>1)

#用0填充：update sale set city = 0 where city = NULL#删除有缺失值的行：delete from sale where city = NULL;

SELECT * from sale where salesman = "张爱" and city = "北京"and orderaccount >=6000;

SELECT * from sale where inventoryname like "%三星%" or 存货名称 like "%索尼%";

SELECT city,sum(`profit`) from saleWHERE city = "北京"GROUP BY `city`;

#有多少个？SELECT COUNT(*) from sale where inventoryname like "%三星%"and `tax` > 1000 ;
#这些订单的利润总和和平均利润是多少？SELECT `ordernum`,SUM(profit),AVG(`profit`) from sale where inventoryname like "%三星%"and `tax` > 1000 GROUP BY `ordernum`;

SELECT trim(inventoryname) from sale;

SELECT city,ordernum,(Nontaxamount - profit) as cost from saleorder by cost DESC;