我有一张有 260 万条记录的表。它看起来像这样:
email prject_name
rafael.nadal@xyz.com lab1
rafael.nadal@xyz.com lab2
rafael.nadal@xyz.com lab3
TEST@TEST.COM shift1
TEST@TEST.COM shift2
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但我希望我的桌子看起来像这样:
email project_name
rafael.nadal@xyz.com lab1, lab2, lab3
TEST@TEST.COM shift1, shift2, shift3
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我用过这个查询
select distinct email ,
STUFF((Select ','+project_name
from dbo.[UMG sent 2016] as T1
where T1.email=T2.email
FOR XML PATH('')),1,1,'') from dbo.[UMG sent 2016] as T2;
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它已经运行了5个小时。
如何加快流程?