mysql 行转列 case when 和聚合函数实现

一、原始数据## 二、行转列

第一步

SELECTCASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '100' THEN aaa.budget_cost_budget ELSE 0 END  b1,CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '300' THEN aaa.budget_cost_budget ELSE 0 END  b2,CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '200' THEN aaa.budget_cost_budget ELSE 0 END  b3,CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '400' THEN aaa.budget_cost_budget ELSE 0 END  b4,CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '500' THEN aaa.budget_cost_budget ELSE 0 END  b5 
FROMffff_info aaa 
WHEREaaa.budget_dh = 1 AND aaa.project_id = '04af0af9-c96d-4744-92d5-3967975b9f6e'

在这里插入图片描述

第二步

SELECTmax( CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '100' THEN aaa.budget_cost_budget ELSE 0 END ) b1,max( CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '300' THEN aaa.budget_cost_budget ELSE 0 END ) b2,max( CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '200' THEN aaa.budget_cost_budget ELSE 0 END ) b3,max( CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '400' THEN aaa.budget_cost_budget ELSE 0 END ) b4,max( CASE WHEN SUBSTRING( aaa.cost_code, 1, 3 ) = '500' THEN aaa.budget_cost_budget ELSE 0 END ) b5 
FROMffff_info aaa 
WHEREaaa.budget_dh = 1 AND aaa.project_id = '04af0af9-c96d-4744-92d5-3967975b9f6e' 
GROUP BYaaa.project_id