ASP.NET Core 7.0 的新增功能

使用Linq来查询Json

使用示例

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var postsWithViews = await context.Posts.Where(post => post.Metadata!.Views > 3000)
    .AsNoTracking()
    .Select(
        post => new
        {
            post.Author!.Name,
            post.Metadata!.Views,
            Searches = post.Metadata.TopSearches,
            Commits = post.Metadata.Updates
        })
    .ToListAsync();

EFCore 7翻译后的SQL语句为

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SELECT [a].[Name],
       CAST(JSON_VALUE([p].[Metadata],'$.Views') AS int),
       JSON_QUERY([p].[Metadata],'$.TopSearches'),
       [p].[Id],
       JSON_QUERY([p].[Metadata],'$.Updates')
FROM [Posts] AS [p]
LEFT JOIN [Authors] AS [a] ON [p].[AuthorId] = [a].[Id]
WHERE CAST(JSON_VALUE([p].[Metadata],'$.Views') AS int) > 3000

注意的是，JSON_VALUE、JSON_QUERY被用来查询Json文档的部分。