oracle先排序再分页

2019年10月2日 165次阅读 来源: Corwien

Oracle排序分页查询和MySQL数据库的语句还不一样，这里做简单的记录。

按操作时间排序1

SELECT A.*, ROWNUM RN FROM (SELECT * FROM v_log) A ORDER BY operatetime DESC

结果

《oracle先排序再分页》

可以发现，按时间排序了，但是rownum并不是从小到大，因为oracle是先生成rownum，再进行排序，需要在套一层查询

按操作时间排序2

SELECT T.*, rownum RN FROM(
      SELECT * FROM (SELECT * FROM v_log) ORDER BY operatetime DESC 
    ) T

结果：

《oracle先排序再分页》
顺序正确，rownum正确，在此基础上再套一层查询进行分页

按操作时间排序并分页

SELECT T2.* from(    
SELECT T.*, rownum RN FROM(
SELECT * FROM (SELECT * FROM v_log) ORDER BY operatetime DESC 
)T) T2 WHERE RN BETWEEN 1 and 10

《oracle先排序再分页》

测试

SELECT * FROM (
        SELECT A."sku", ROWNUM rn, A."goods_sn" 
        FROM AMZ_HUOPIN_SKU A
        WHERE ROWNUM <= 10 ORDER BY A."goods_sn" DESC) temp
WHERE temp.rn > 0;

SELECT A."sku", A."goods_sn", ROWNUM RN FROM AMZ_HUOPIN_SKU A ORDER BY A."sku" DESC


## 子查询先找出所有，然后再rownum,rownum 为伪列，后再排序
SELECT A."sku", A."goods_sn", ROWNUM RN FROM (SELECT * FROM AMZ_HUOPIN_SKU) A ORDER BY A."sku" DESC

## 因为oracle是先生成rownum，再进行排序，需要在套一层查询,即先拍好序，然后再生成rownum
SELECT T."sku", T."goods_sn", ROWNUM RN FROM (SELECT * FROM (SELECT * FROM AMZ_HUOPIN_SKU) ORDER BY "sku" DESC
) T

## 上边的这两个语句是等价的
SELECT T."sku", T."goods_sn", ROWNUM RN FROM (SELECT * FROM AMZ_HUOPIN_SKU ORDER BY "sku" DESC
) T


SELECT T2.* FROM(
SELECT T."sku", T."goods_sn", ROWNUM RN FROM (SELECT * FROM AMZ_HUOPIN_SKU ORDER BY "sku" DESC
) T) T2 WHERE RN BETWEEN 0 AND 10

综合查询

# 1、子句查询，这条语句可以加条件WHERE
SELECT * FROM (SELECT A."sku", A."goods_sn", A."category",A."color_name", A."size_name", A."fnsku",H.QTY,H.WAREHOUSEID,H.F_CREATE_TIME FROM AMZ_HUOPIN_SKU A 
LEFT JOIN HWC_CAMEL_INV_ALL H ON A."fnsku" = H.SKU)

# 2、排序

SELECT * FROM (SELECT * FROM (SELECT A."sku", A."goods_sn", A."category",A."color_name", A."size_name", A."fnsku",H.QTY,H.WAREHOUSEID,H.F_CREATE_TIME FROM AMZ_HUOPIN_SKU A 
LEFT JOIN HWC_CAMEL_INV_ALL H ON A."fnsku" = H.SKU)) ORDER BY "goods_sn" DESC

# 3、排序之后，再获取ROWNUM
SELECT T.*, ROWNUM RN FROM (SELECT * FROM (SELECT * FROM (SELECT A."sku", A."goods_sn", A."category",A."color_name", A."size_name", A."fnsku",H.QTY,H.WAREHOUSEID,H.F_CREATE_TIME FROM AMZ_HUOPIN_SKU A 
LEFT JOIN HWC_CAMEL_INV_ALL H ON A."fnsku" = H.SKU)) ORDER BY "goods_sn" DESC) T

# 4、再根据获取到的ROWNUM按照顺序进行分页
SELECT R.* FROM(
  SELECT T.*, ROWNUM RN FROM (SELECT * FROM (SELECT * FROM (SELECT A."sku", A."goods_sn", A."category",A."color_name", A."size_name", A."fnsku",H.QTY,H.WAREHOUSEID,H.F_CREATE_TIME FROM AMZ_HUOPIN_SKU A 
  LEFT JOIN HWC_CAMEL_INV_ALL H ON A."fnsku" = H.SKU WHERE A."goods_sn" = 'K832026565')) ORDER BY "goods_sn" DESC) T
) R WHERE RN BETWEEN 10 AND 20

注：本文为转载，原文地址：oracle先排序再分页

    原文作者：Corwien
    原文地址: https://segmentfault.com/a/1190000018271396
    本文转自网络文章，转载此文章仅为分享知识，如有侵权，请联系博主进行删除。
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