如何将 MySQL 行折叠到列结果答案

【问题标题】：How to Collapse MySQL Rows to Columns Result如何将 MySQL 行折叠到列结果
【发布时间】：2010-10-29 17:45:41
【问题描述】：

有一个查询，我想获取：

Username 附加到当前机会记录的用户
Sales Stage 与每个机会记录关联
Dollar 与机会记录关联的金额

我想：

获取当前的 IF STATEMENT 结果并将其折叠

当前查询：

$sql = "SELECT u.user_name as USER,
               if(o.sales_stage='Prospecting', o.amount, '') as PROSPECTING,
               if(o.sales_stage='Needs Analysis', o.amount, '') as NEEDS_ANALYSIS,
               if(o.sales_stage='Closed Won', o.amount, '') as CLOSED_WON
          FROM opportunities o,
               users u
         WHERE o.assigned_user_id = u.id
      GROUP BY u.user_name ";

当前结果：

USER   PROSPECTING  NEEDS_ANALYSIS  CLOSED_WON
---------------------------------------------
chris  10000        0               0
chris  0            15000           0
chris  0            0               10000
sara   5000         0               0
sara   0            0               10000

我想做的是折叠我只有 1 个用户的结果，以及每个销售阶段他们各自的金额

USER   PROSPECTING  NEEDS_ANALYSIS  CLOSED_WON
---------------------------------------------
chris  10000        15000           10000
sara   5000         0               10000

【问题讨论】：

立即想到的是用三个不同的别名加入机会表，然后选择适当的 alias.fieldname....

标签： php mysql sql pivot

【解决方案1】：

“折叠”通常称为“透视”，因为您将行转换为列数据。使用：

  SELECT u.user_name as USER,
         MAX(CASE WHEN o.sales_stage = 'Prospecting' THEN o.amount END) AS PROSPECTING,
         MAX(CASE WHEN o.sales_stage = 'Needs Analysis' THEN o.amount END) AS NEEDS_ANALYSIS,
         MAX(CASE WHEN o.sales_stage = 'Closed Won' THEN o.amount END) AS CLOSED_WON
    FROM OPPORTUNITIES o
    JOIN USERS u ON u.id = o.assigned_user_id
GROUP BY u.user_name

【讨论】：

【解决方案2】：

您需要将聚合函数添加到您的 $ 金额...即：

SELECT

u.user_name as USER,

if(o.sales_stage='Prospecting', SUM(o.amount), '') as PROSPECTING,

if(o.sales_stage='Needs Analysis', SUM(o.amount), '') as NEEDS_ANALYSIS,

if(o.sales_stage='Closed Won', SUM(o.amount), '') as CLOSED_WON

FROM

opportunities o,

users u

WHERE

o.assigned_user_id = u.id

GROUP BY

u.user_name

编辑

现在我想一想，您可能仍然会得到单独的行，因为同一用户的记录之间的销售阶段可能不同。您是否考虑过使用例程对每个销售阶段进行计算，以将结果折叠到每个用户一行？

【讨论】：

【解决方案3】：

您可以将当前查询包装在另一个查询中，如下所示：

select subquery.user, 
       sum(subquery.propspecting), 
       sum(subquery.needs_analysis), 
       sum(subquery.closed_won) 
from (*...your query goes here*) subquery 
group by subquery.user

【讨论】：