1.索引
group by where having order by
https://blog.csdn.net/whathellll/article/details/80765020concat
https://baijiahao.baidu.com/s?id=1595349117525189591&wfr=spider&for=pc倆練習(xí)
https://blog.csdn.net/feinifi/article/details/80279897
image.png
6.round
https://www.runoob.com/sql/sql-func-round.html
https://blog.csdn.net/chinabestchina/article/details/72799826
7.count
image.png
8.distinct
image.png
9.group by
image.png
10.having
image.png
image.png
11.執(zhí)行順序
image.png
12.子查詢
image.png
image.png
image.png
image.png
image.png
image.png
image.png
13.自連接,一個題
image.png
image.png
14.表和視圖
https://blog.csdn.net/m0_37248802/article/details/80563691
