Oracle数据库row_number() over统计前15名企业， wm_concat(case when then)行转列
来源：程序员人生 发布时间：2015-03-07 13:02:14 阅读次数：4212次
1.
ROW_NUMBER() OVER函数的基本用法
语法：ROW_NUMBER() OVER(PARTITION BY COLUMN ORDER BY COLUMN)
例如：row_number() OVER (PARTITION BY
COL1 ORDER BY COL2) 表示根据COL1分组，在分组内部根据 COL2排序，而此函数计算的值就表示每组内部排序后的顺序编号（组内连续的唯1的)
如：不同的产品种别和计量单位下，查询所有企业的排名。
SELECT product_type 产品种别,
prickle 计量单位,
production_name 企业名称,
row_number() over(partition by product_type, prickle order by sum(pur.purchase_num) desc) 名次
from t_purchase_info pur
group by production_name, product_type, prickle
参考：http://www.cnblogs.com/fxgachiever/archive/2010/09/15/1826792.html
2.列转行 wm_concat(case when then)
查出来不同的产品种别不同的计量单位下，统计出前15名企业的申报量
查出来的效果是：
select product_type 产品种别,
prickle 计量单位,
wm_concat(case
when r = 1 then
production_name
end) 第1名,
wm_concat(case
when r = 1 then
value1
end) 申报量,
wm_concat(case
when r = 2 then
production_name
end) 第2名,
wm_concat(case
when r = 2 then
value1
end) 申报量,
wm_concat(case
when r = 3 then
production_name
end) 第3名,
wm_concat(case
when r = 3 then
value1
end) 申报量,
wm_concat(case
when r = 4 then
production_name
end) 第4名,
wm_concat(case
when r = 4 then
value1
end) 申报量,
wm_concat(case
when r = 5 then
production_name
end) 第5名,
wm_concat(case
when r = 5 then
value1
end) 申报量,
wm_concat(case
when r = 6 then
production_name
end) 第6名,
wm_concat(case
when r = 6 then
value1
end) 申报量,
wm_concat(case
when r = 7 then
production_name
end) 第7名,
wm_concat(case
when r = 7 then
value1
end) 申报量,
wm_concat(case
when r = 8 then
production_name
end) 第8名,
wm_concat(case
when r = 8 then
value1
end) 申报量,
wm_concat(case
when r = 9 then
production_name
end) 第9名,
wm_concat(case
when r = 9 then
value1
end) 申报量,
wm_concat(case
when r = 10 then
production_name
end) 第10名,
wm_concat(case
when r = 10 then
value1
end) 申报量,
wm_concat(case
when r = 11 then
production_name
end) 第101名,
wm_concat(case
when r = 11 then
value1
end) 申报量,
wm_concat(case
when r = 12 then
production_name
end) 第102名,
wm_concat(case
when r = 12 then
value1
end) 申报量,
wm_concat(case
when r = 13 then
production_name
end) 第103名,
wm_concat(case
when r = 13 then
value1
end) 申报量,
wm_concat(case
when r = 14 then
production_name
end) 第104名,
wm_concat(case
when r = 14 then
value1
end) 申报量,
wm_concat(case
when r = 15 then
production_name
end) 第105名,
wm_concat(case
when r = 15 then
value1
end) 申报量
from (SELECT r, production_name, product_type, prickle, value1
FROM (SELECT row_number() over(partition by product_type, prickle order by sum(pur.purchase_num) desc) r,
pur.production_name,
pur.product_type,
prickle,
to_char(round(sum(pur.purchase_num), 2),
'9999999999999999999.99') value1
FROM t_purchase_info pur, t_sgproject_info pro
WHERE 1 = 1
AND pro.id = pur.project_id
AND (pro.gclb = '房屋建筑工程' OR pro.gclb IS NULL)
AND pro.status != 9
AND product_regdate >=
to_date('2014-01-01', 'yyyy-mm-dd hh24:mi:ss')
AND product_regdate <=
to_date('2014⑴2⑶1 23:59:59', 'yyyy-mm-dd hh24:mi:ss')
AND sgproject_type = 1
GROUP BY production_name, product_type, prickle)
WHERE r <= 15
ORDER BY product_type, prickle, r)
group by product_type, prickle
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