SqlServer 索引

BranchInfo 表索引设置 --表扫描,索引无效 SELECT * FROM dbo.BranchInfo WHERE LEN(PoiId)>0 --索引扫描 SELECT * FROM dbo.BranchInfo WHERE PoiId<>'' --索引扫描 SELECT * FROM dbo.BranchInfo WHERE PoiId IS NOT NULL AND PoiId<>'

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