ORACLE大数据量下的分页解决方法: http://ddkangfu.blog.51cto.com/311989/1425797/
oracle 分页数据重复数据不正确: https://my.oschina.net/u/852445/blog/402325
实例:
SELECT * FROM ( SELECT RS.AMOUNT,RS.AREA,RS.AREANAME,[color=red]ROWNUM rn FROM ( SELECT ( CASE WHEN oy.AMOUNT IS NULL THEN ny.AMOUNT-0 WHEN ny.AMOUNT IS NULL THEN 0-oy.AMOUNT ELSE ny.AMOUNT-oy.AMOUNT END) AS amount,NY.AREA,NY.areaName FROM (SELECT "SUM"(VI.AMOUNT) AS AMOUNT,VI.AREA,dm.AREA_NAME as areaName FROM VI_INCOME_ITEM_MAPPING VI LEFT JOIN DM_AREA dm ON VI.AREA = dm.AREA_CODE WHERE VI.T_ITEM = #{BudgetTItem,jdbcType=VARCHAR} AND VI.BLEVEL ='3' AND "SUBSTR"(VI.TXN_DATE,1,6) <![CDATA[ >= ]]> #{startMonth,jdbcType=VARCHAR} AND "SUBSTR"(VI.TXN_DATE,6) <![CDATA[ <= ]]> #{endMonth,jdbcType=VARCHAR} GROUP BY VI.AREA,dm.AREA_NAME) ny LEFT JOIN (SELECT "SUM"(VI.AMOUNT) AS AMOUNT,dm.AREA_NAME as areaName FROM VI_INCOME_ITEM_MAPPING VI LEFT JOIN DM_AREA dm ON VI.AREA = dm.AREA_CODE WHERE VI.T_ITEM = #{BudgetTItem,6) <![CDATA[ >= ]]> #{lastStartMonth,jdbcType=VARCHAR} AND "SUBSTR"(VI.TXN_DATE,6) <![CDATA[ <= ]]> #{lastEndMonth,jdbcType=VARCHAR} GROUP BY VI.AREA,dm.AREA_NAME) oy ON NY.AREA = OY.AREA ORDER BY amount DESC ) [color=red]rs WHERE ROWNUM <= 10) WHERE rn >0
注意红色字体内层用ROWNUM,外层用RN,Oracle 一般第一次select时,有ROWNUM,可在第二层分页
分页两种方法:
第一种:
SELECT * FROM (SELECT t.*,ROWNUM as rowno FROM (SELECT * FROM test ORDER BY ADD_TIME ) t ) WHERE rowno BETWEEN 200001 AND 300000;
第二种:
SELECT * FROM ( SELECT t.*,ROWNUM as rowno FROM (SELECT * FROM test ORDER BY ADD_TIME) t WHERE ROWNUM <= 300000) WHERE rowno >=200001
第二种比第一种有效,因为第二种锁定了分页结果集,而第一种是从表所有记录中,分页;
对于两层嵌套的分页查询如:
实例:
select (select * from test ORDER BY ADD_TIME) where ROWNUM between 100000 and 200000对于含排序(ORDER BY ADD_TIME), 则排序字段ADD_TIME字段必须是唯一索引,否则已出现 结果集为空,或数据重复,含排序的正确做法如上面两种分页方式,再加一层嵌套。 原文链接:https://www.f2er.com/oracle/212970.html