一、行列轉換

　　基本思路：

　　　　1. 將數據轉轉為標書數據，如圖所示

　　　　2. 使用笛卡爾積做行列轉換

select 
    sum(case when childr=‘餐飲‘ then money end ) as ‘餐飲‘ , 
    sum(case when childr=‘通訊‘ then money end ) as ‘通訊‘ ,
    sum(case when childr=‘娛樂‘ then money end ) as ‘娛樂‘ 
from 
    (select childr, convert(sum(money
 
), decimal(10,2)) as money from wx_spend  group by childr) tmp;

一、單列轉多行轉換

原數據樣式

　　　　　　處理後數據樣式

　　　　SQL語句

CREATE TABLE tmp_sequence (id INT PRIMARY KEY AUTO_INCREMENT);
INSERT INTO tmp_sequence VALUES(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),(),();

SELECT 
    name, 
 
REPLACE(SUBSTRING(SUBSTRING_INDEX(courseinfo, ‘,‘, a.id), CHAR_LENGTH(SUBSTRING_INDEX(courseinfo, ‘,‘, a.id-1)) + 1), ‘,‘ ,‘‘) AS courseinfo
FROM 
    tmp_sequence a 
CROSS JOIN 
    (SELECT name, concat(courseinfo,",") AS courseinfo, LENGTH(courseinfo) - LENGTH(REPLACE(courseinfo, ‘,‘, ‘‘)) + 1
 
 AS size FROM W_SalesCoursePackageInfo LIMIT 1,1) b
ON a.id <= b.size

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