javascript - LinqJs - 使用非重复计数进行分组

Question

我正在使用 LinqJs 并尝试创建包含特定数据集的分组集。我已经用 MS-SQL 编写了查询，并希望获得一些帮助以将其转换为 LinqJs。我的主要问题是试图获得非重复计数。 这是我的带有示例表和数据的 SQL 查询。

declare @table TABLE(appID int,appName varchar(50), dcID varchar(20), projectID varchar(10))

INSERT INTO @table
values ('160146','TAP','GFTS2018123','P1'),('160146','TAP','GFTS2018123','P2')

select appID, appName, dcID, count(distinct(dcID)) as DcCount, count(distinct(projectID)) as ProjectCount 
from @table 
group by appID, appName, dcID

这是我不完整的 LinqJs 查询

var statusData = Enumerable.From(data).GroupBy(
                null,
                null,
                "{ AppID: $.AppID, AppName: $.AppName, dcID: $.dcID,DcCount: $$.Count('$.dcID'), projectCount:$$.Count('$.projectID') }",
                "$.AppID"
            ).ToArray();

我期望的输出是

appID   appName dcID        DcCount ProjectCount
160146  TAP     GFTS2018123 1       2

Answer 1

您可以链接 Distinct 和 Count。

DcCount: $$.Distinct('$.dcID').Count('$.dcID')

var data = [
        { appID: '160146', appName: 'TAP', dcID: 'GFTS2018123', projectID: 'P1' },
        { appID: '160146', appName: 'TAP', dcID: 'GFTS2018123', projectID: 'P2' },
        { appID: '160147', appName: 'TAP', dcID: 'GFTS2018123', projectID: 'P1' },
        { appID: '160148', appName: 'TAP', dcID: 'GFTS2018123', projectID: 'P2' },
        { appID: '160148', appName: 'TAP', dcID: 'GFTS2018124', projectID: 'P3' },
        { appID: '160148', appName: 'TAP', dcID: 'GFTS2018124', projectID: 'P3' },
        { appID: '160148', appName: 'TAP', dcID: 'GFTS2018125', projectID: 'P3' },
        { appID: '160149', appName: 'TAP', dcID: 'GFTS2018123', projectID: 'P2' }
    ],
    statusData = Enumerable
        .From(data)
        .GroupBy(
            null,
            null,
            "{ AppID: $.appID, AppName: $.appName, dcID: $.dcID, DcCount: $$.Distinct('$.dcID').Count('$.dcID'), projectCount: $$.Distinct('$.projectID').Count('$.projectID') }",
            "$.appID"
        )
        .ToArray();

console.log(statusData);

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