Oracle 行列轉換函式pivot的使用(二)
阿新 • • 發佈:2018-11-23
關鍵函式pivot,其用法如下 pivot(聚合函式 for 列名 in(型別))
select * from table_name pivot(max(column_name) --行轉列後的列的值value,聚合函式是必須要有的
for column_name in(value_1,value_2,value_3) --需要行轉列的列及其對應列的屬性1/2/3
)
1、首先舉一個簡單的例子,建立一個數據表
1 create table tmp as select * from ( 2 select '張三' student,'語文' course ,78 score from dual union all 3 select '張三','數學',87 from dual union all 4 select '張三','英語',82 from dual union all 5 select '張三','物理',90 from dual union all 6 select '李四','語文',65 from dual union all 7select '李四','數學',77 from dual union all 8 select '李四','英語',65 from dual union all 9 select '李四','物理',85 from dual);
先使用decode或case when方法
1 select 2 student, 3 max(decode(course, '語文', score)) 語文, 4 max(decode(course, '數學', score)) 數學, 5 max(decode(course, '英語', score)) 英語,6 max(decode(course, '物理', score)) 物理, 7 sum(score) total 8 from tmp 9 group by student; 10 ----------------------------------------- 11 select 12 student, 13 max(case when course = '語文' then score end) 語文, 14 max(case when course = '數學' then score end) 數學, 15 max(case when course = '英語' then score end) 英語, 16 max(case when course = '物理' then score end) 物理, 17 sum(score) total 18 from tmp 19 group by student;
pivot的使用
1 select t.*, 2 (t.語+t.數+t.外+t.物) as total 3 from 4 (select * 5 from tmp pivot ( max(score) for course in ('語文' as 語 , '數學' as 數, '英語' as 外,'物理' as 物) ) 6 ) t;
結果同上
2、實際開發遇到的問題
有一張目標值表,年、月、日的值都是分開多行顯示,現需合併成一行顯示,具體資料如下:(type:1-->日,2-->月,3-->年;targetvalue:目標值)
select * from MOVEBI.T_GMS_MBI_TARGET_DATA where targetcode = '31227061'
此資料必須先進性處理,要保證資料可以聚合成一條,若直接使用會出現下列情況:
select * from MOVEBI.T_GMS_MBI_TARGET_DATA pivot(max(targetvalue) for type in (1 day_value,2 mon_value,3 year_value)) where targetcode = '31227061';
這不是我們想要的結果,具體改進法法如下:
1 --方法一:對結果處理 2 select max(datatime) datatime 3 ,usercode 4 ,deptcode 5 ,deptname 6 ,targetcode 7 ,targetname 8 ,sum(coalesce(day_value,0)) day_value 9 ,sum(coalesce(mon_value,0)) mon_value 10 ,sum(coalesce(year_value,0)) year_value 11 from( 12 select datatime,usercode,deptcode,deptname,targetcode,targetname,day_value,mon_value,year_value 13 from MOVEBI.T_GMS_MBI_TARGET_DATA 14 pivot(max(targetvalue) for type in (1 day_value,2 mon_value,3 year_value)) where targetcode = '31227061') 15 group by usercode 16 ,deptcode 17 ,deptname 18 ,targetcode 19 ,targetname; 20 --方法二:對原始表處理 21 select * 22 from (select '20181017' datatime, 23 usercode, 24 deptcode, 25 deptname, 26 targetcode, 27 targetname, 28 targetvalue, 29 type 30 from MOVEBI.T_GMS_MBI_TARGET_DATA 31 where datatime in ('20181017', '201810') 32 and targetcode = '31227061') t 33 pivot(max(targetvalue) for type in (1 day_value,2 mon_value,3 year_value)) where targetcode = '31227061';
(注:此為學習記錄筆記,僅供參考若有問題請指正,後續補充......)
參考文件:https://www.cnblogs.com/harvey888/p/6735093.html
參考文件:https://www.cnblogs.com/markfeifei/p/4009343.html