SQL如何将类似的记录合并到同一个表中的单行？

Question

我目前正在尝试清理前员工创建的邮件订阅者数据库.我已经能够整合和修复大多数问题(主要是重复),但我有订阅者的实例有重复记录,因为他们订阅了多个区域.我想要做的是将这些重复记录合并为1.

这是我要合并的重复记录的编辑实际示例:

id     first     last    address    truck    machinery    gl    ne    nw
------------------------------------------------------------------------
1      Chuck     G....   12 Lorem   1                     1
2      Chuck     G....   12 Lorem            1                        1
3      Chuck     G....   12 Lorem            1                  1

我想将2合1记录合并,并删除所有重复项(有些重复项最多9个),如下所示:

id     first     last    address    truck    machinery    gl    ne    nw
------------------------------------------------------------------------
1      Chuck     G....   12 Lorem   1        1            1     1     1

Answer 1

使用Group By和Max/Min聚合

SELECT id, 
       first, 
       last, 
       address, 
       Max(truck)     AS truck, 
       Max(machinery) AS machinery, 
       Max(gl)        AS gl, 
       Max(ne)        AS ne, 
       Max(nw)        AS nw 
FROM   yourtable 
GROUP  BY id, 
          first, 
          last, 
          address