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2021/06/27 16:28

投稿

sazi
sazi

スコア25329

test CHANGED
@@ -29,3 +29,37 @@
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  on usr.id = his.userid
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  ```
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+
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+ projectから取得する項目が限定されるなら、いっそ以下の方が高速だと思います。
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+ ```SQL
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+ select prj.*, usr.username
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+ from (
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+ select prj.id, prj.projectname
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+ , max(his.updatedt) as lastupdate
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+ from project as prj
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+ left join history as his
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+ on prj.id = his.projectid
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+ group by prj.id, prj.projectname
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+ ) as prj
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+ left join history as his
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+ on prj.id = his.projectid
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+ and prj.lastupdate=his.updatedt
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+ left join user as usr
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+ on usr.id = his.userid
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+ ```