Commit 4a539ff

committed

join优化

1 parent 11c7c20 commit 4a539ffCopy full SHA for 4a539ff

File tree

-1

lines changed

-1

lines changed

Lines changed: 6 additions & 1 deletion

Original file line number	Diff line number	Diff line change
`@@ -86,7 +86,12 @@ select a.user_name , a.over , b.over from user1 a left join user2 b on a.user_na`
`86`	`86`
`87`	`87`
`88`	`88`
`89`		`-`
	`89`	`+********************************************************************************`
	`90`	`+使用join + having优化聚合子查询:`
	`91`	`+select a.user_name,b.timestr,b.kills from user1 a join user_kills b on a.id = b.user_id`
	`92`	`+ join user_kills c on c.user_id = b.user_id`
	`93`	`+ group by a.user_name,btimestr,b.kills`
	`94`	`+ having b.kills = max(c.kills);`
`90`	`95`
`91`	`96`
`92`	`97`

Comments

(0)