sql大數據多條件查詢索引優化

此優化的前提可以稱之為最近流行的頭條人物“許三多”，總數據多，查詢條件多，返回列多

優化前分頁查詢內部select列為需要的全部列，優化后內部select只返回ID主鍵，外部查詢關聯原數據表，然后查出所需要的列

 

例子1

優化前：

 

select t.* from (
        select r.* ,row_number() over(order by r.id desc) row from tab(nolock) r
        where 1=1 and r.IsDelete=0 and r.Status>0 and r.PlatformID=1 and r.CreateUser=100000
) as t  where row between 1 and 10

select t.* from (
        select r.* ,row_number() over(order by r.id desc) row from tab(nolock) r 
        where 1=1 and r.IsDelete=0 and r.Status>0 and r.PlatformID=1 and r.CreateUser=100000 	
) as t  where row between 1 and 10

 

優化后：

 

select r.* from (
        select r.ID ,row_number() over(order by r.id desc) row from tab(nolock) r
        where 1=1 and r.IsDelete=0 and r.Status>0 and r.PlatformID=1 and r.CreateUser=100000
) as t join tab r on r.id=t.id where row between 1 and 10

select r.* from (
        select r.ID ,row_number() over(order by r.id desc) row from tab(nolock) r 
        where 1=1 and r.IsDelete=0 and r.Status>0 and r.PlatformID=1 and r.CreateUser=100000 	
) as t join tab r on r.id=t.id where row between 1 and 10

最近又有一個例子

例子2

優化前：tablA數據量1千多萬，tablB數據量幾百萬，查詢速度11秒多

 

select * from (
        select d.LessonPlanID,d.ResUrl,p.createID,p.CreateTime,row_number() over(order by d.id desc) row
        from tablA(nolock) d
        join tablB(nolock) p on p.id=d.lessonplanid
        where p.createID in(109486,103295,103298,109347,130346,181382,330312)
    ) t where t.row between 1 and 20

select * from (
	    select d.LessonPlanID,d.ResUrl,p.createID,p.CreateTime,row_number() over(order by d.id desc) row
	    from tablA(nolock) d 
		join tablB(nolock) p on p.id=d.lessonplanid
	    where p.createID in(109486,103295,103298,109347,130346,181382,330312)
	) t where t.row between 1 and 20 

 

優化后：查詢速度14毫秒

 

select d.LessonPlanID,d.ResUrl,p.createID,p.CreateTime from (
        select  d.id,row_number() over(order by d.id desc) row
        from tablA(nolock) d
        join tablB(nolock) p on p.id=d.lessonplanid
        where p.createID in(109486,103295,103298,109347,130346,181382,330312)
) t join tablA(nolock) d on d.id=t.id   join tablB(nolock) p on p.id=d.lessonplanid
 where t.row between 1 and 20

select d.LessonPlanID,d.ResUrl,p.createID,p.CreateTime from (
	    select  d.id,row_number() over(order by d.id desc) row
	    from tablA(nolock) d 
		join tablB(nolock) p on p.id=d.lessonplanid
	    where p.createID in(109486,103295,103298,109347,130346,181382,330312)
) t join tablA(nolock) d on d.id=t.id	join tablB(nolock) p on p.id=d.lessonplanid
 where t.row between 1 and 20