oracle先排序再分页

iceghostsc 2019-07-01

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

相关推荐

jiong / 0评论 2020-09-17