Mysql数据显示多行而不是一行

Question

我想知道如何根据字段值将上面的数据显示到一行中，我做了一个案例选择，但结果如下图

(SELECT lead_id,
 case lead_id
 case field_number when 1  then value  end as firstname

 case field_number when 1 then value end as firstname,
 case field_number when 2 then value end as lastname,
 case field_number when 10 then value end as email,

Answer 1

您正在尝试使用条件聚合来做到这一点(这意味着您缺少一个 group by 子句和一个最大/最小函数):

SELECT lead_id,
       MAX(CASE WHEN field_number = 1 then value end) as firstname,
       MAX(CASE WHEN field_number = 2 then value end) as lastname,
       MAX(CASE WHEN field_number = 10 then value end) as email
FROM YourTable
GROUP BY lead_id