oracle高效分頁(yè)查詢 oracle怎么實(shí)現(xiàn)多表連接查詢并分頁(yè)?
oracle怎么實(shí)現(xiàn)多表連接查詢并分頁(yè)?oracle使用rownum偽列可以實(shí)現(xiàn)分頁(yè),三表連接分頁(yè)示例代碼如下:select * from (select rownum r,k.kch,k.kcm,c
oracle怎么實(shí)現(xiàn)多表連接查詢并分頁(yè)?
oracle使用rownum偽列可以實(shí)現(xiàn)分頁(yè),三表連接分頁(yè)示例代碼如下:
select * from (select rownum r,k.kch,k.kcm,cj.cj,x.xh,x.xm from KCB k,CJB cj,XSB x where k.kch = cj.kch and cj.xh = x.xh and rownum<=10) where r>0
特別注意這樣外層查詢時(shí)由于內(nèi)層查詢的字段有重復(fù)列名,所以內(nèi)層查詢最后不要用*。取完每一個(gè)表字段,這樣很容易報(bào)錯(cuò)(“無(wú)效字段”)
oracle數(shù)據(jù)庫(kù)怎么實(shí)現(xiàn)分頁(yè)?
您好:oracle查詢分頁(yè)可分為兩種情況,一種使用的是rownum ,另外一種則是使用 row_number() over(order by column_name desc)。1.使用rownum分頁(yè)查詢,可用以下方式:select t2.* from (select t1.*,rownum as rn from table_name t1 where 1=1 and rownum <= page * page_size) t2 where t2.rn > (page - 1) * page_size2.使用 row_number() over() 分頁(yè)查詢select t2.* from (select t1.*,row_number() over(order by column_name desc) as rn from table_name t1 where 1=1 )t2 where t2.rn > (page-1)* page_size and t2.rn <= page * page_size這種方式,也是可以分頁(yè)的。希望能幫助您!
jdbctemplate怎么實(shí)現(xiàn)oracle分頁(yè)查詢?
sql語(yǔ)句如下:
分頁(yè)1
SELECT *
FROM (Select ROWNUM AS ROWNO, T.*
from 表名 T(別名)
where 表字段 between to_date("20060501", "yyyymmdd") and to_date("20060731", "yyyymmdd")
AND ROWNUM
WHERE TABLE_ALIAS.ROWNO >= 10
經(jīng)過(guò)測(cè)試,此方法成本最低,只嵌套一層,速度最快,即使查詢的數(shù)據(jù)量再大,也幾乎不受影響,速度依然.
分頁(yè)2:
SELECT *
FROM (SELECT TT.*, ROWNUM AS ROWNO
FROM (Select t.*
from 表名 T(別名)
where flight_date between to_date("20060501", "yyyymmdd") and
to_date("20060531", "yyyymmdd")
ORDER BY FACT_UP_TIME, flight_no) TT(別名二)
WHERE ROWNUM
where TABLE_ALIAS.rowno >= 10
經(jīng)過(guò)測(cè)試,此方法隨著查詢范圍的擴(kuò)大,速度也會(huì)越來(lái)越慢,