使用偏移和限制应用分页我发现列不存在

问题描述 投票：0回答：1

我在 power bi 中有这个公式来从外部 Api 获取数据：-

let
body=Text.Combine({"sAPIKey=",ApiKey}),
SourceAPILogin=Json.Document(
Web.Contents(
SmartAPI,
[
RelativePath="apilogin",
Headers=[Accept="application/json", #"Content-Type"="application/x-www-form-urlencoded",#"API-Key"=Token],
Content=Text.ToBinary(body)
]
)
),
tblGetUID = Table.FromList(SourceAPILogin, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
expGetUID = Table.ExpandRecordColumn(tblGetUID, "Column1", {"UID", "LanguageCode", "DatabaseVersion"}, {"Column1.UID", "Column1.LanguageCode", "Column1.DatabaseVersion"}),
GetUID = expGetUID{0}[Column1.UID],
Source=Json.Document(
Web.Contents(
SmartAPI,
[
RelativePath = "jobs", //RESTAPI endpoint
//Query = [#"sQueryKey" = QueryKey,#"FilterLocation"="Database"], // QueryParameters
Headers=[Accept="application/json", #"Content-Type"="application/json",#"API-Key"=Token, UID=GetUID, DeviceID=ApiKey] //Headers
]
)
),
#"Converted to Table" = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
//display all the columns from query
Result=Table.ExpandRecordColumn( #"Converted to Table","Column1", Table.ColumnNames(Table.FromRecords(List.Select(Table.Column(#"Converted to Table","Column1"), each _ <> "" and _ <> null))),Table.ColumnNames(Table.FromRecords(List.Select(Table.Column(#"Converted to Table","Column1"), each _ <> "" and _ <> null)))),
#"Changed Type" = Table.TransformColumnTypes(Result,{{"StartedDate", type datetime}})

in
#"Changed Type"

目前我只得到10,000个项目，所以我想使用偏移和限制来应用分页，所以我修改了代码如下：-

let
    // Function to fetch data with pagination
    Fetchjobs = (Offset as number, Limit as number) as table =>
        let
            body = Text.Combine({"sAPIKey=", ApiKey}),
            SourceAPILogin = Json.Document(
                                Web.Contents(
                                    SmartAPI,
                                    [
                                        RelativePath="apilogin",
                                        Headers=[Accept="application/json", #"Content-Type"="application/x-www-form-urlencoded",#"API-Key"=Token],
                                        Content=Text.ToBinary(body)
                                    ]
                                )
                            ),
            tblGetUID = Table.FromList(SourceAPILogin, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
            expGetUID = Table.ExpandRecordColumn(tblGetUID, "Column1", {"UID", "LanguageCode", "DatabaseVersion"}, {"Column1.UID", "Column1.LanguageCode", "Column1.DatabaseVersion"}),
            GetUID = expGetUID{0}[Column1.UID],
            Source = Json.Document(
                        Web.Contents(
                            SmartAPI,
                            [
                                RelativePath = "jobs",
                                Query = [#"offset"=Text.From(Offset), #"limit"=Text.From(Limit)], // Adding Offset and Limit parameters
                                Headers=[Accept="application/json", #"Content-Type"="application/json",#"API-Key"=Token, UID=GetUID, DeviceID=ApiKey] 
                            ]
                        )
                    ),
            tblAll = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
            tableHasRecords = Table.RowCount(tblAll) > 0,
            Result = if tableHasRecords then
                        Table.ExpandRecordColumn(tblAll,"Column1", Table.ColumnNames(Table.FromRecords(List.Select(Table.Column(tblAll,"Column1"), each _ <> "" and _ <> null))),Table.ColumnNames(Table.FromRecords(List.Select(Table.Column(tblAll,"Column1"), each _ <> "" and _ <> null))))
                     else
                        #table(Table.ColumnNames(tblAll), {})
        in
            Result,

    // Initial pagination parameters
    Offset = 0,
    Limit = 10000,
    PageSize = 10000,

    // Loop through pages to get all records
    AllPages = List.Generate(
                    () => [Result = Fetchjobs(Offset, Limit), Offset = Offset + PageSize],
                    each Table.RowCount([Result]) > 0,
                    each [Result = Fetchjobs([Offset], Limit), Offset = [Offset] + PageSize],
                    each [Result]
                ),

    // Combine all the pages into a single table
    tbljobs = Table.Combine(AllPages),

    // Change column types as needed
    #"Changed Type" = Table.TransformColumnTypes(tbljobs,{{"StartedDate", type datetime}})
    
in
    #"Changed Type"

但是应用偏移量和限制后我得到了这个错误：-

Expression.Error: The column 'StartedDate' of the table wasn't found.
Details:
StartedDate

这是我尝试连接到@的API https://developer.smarttid.dk/smartapi/jobs

此外，如果我删除列变换，如下所示：-

let
    // Function to fetch data with pagination
    Fetchjobs = (Offset as number, Limit as number) as table =>
        let
            body = Text.Combine({"sAPIKey=", ApiKey}),
            SourceAPILogin = Json.Document(
                                Web.Contents(
                                    SmartAPI,
                                    [
                                        RelativePath="apilogin",
                                        Headers=[Accept="application/json", #"Content-Type"="application/x-www-form-urlencoded",#"API-Key"=Token],
                                        Content=Text.ToBinary(body)
                                    ]
                                )
                            ),
            tblGetUID = Table.FromList(SourceAPILogin, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
            expGetUID = Table.ExpandRecordColumn(tblGetUID, "Column1", {"UID", "LanguageCode", "DatabaseVersion"}, {"Column1.UID", "Column1.LanguageCode", "Column1.DatabaseVersion"}),
            GetUID = expGetUID{0}[Column1.UID],
            Source = Json.Document(
                        Web.Contents(
                            SmartAPI,
                            [
                                RelativePath = "jobs",
                                Query = [#"offset"=Text.From(Offset), #"limit"=Text.From(Limit)], // Adding Offset and Limit parameters
                                Headers=[Accept="application/json", #"Content-Type"="application/json",#"API-Key"=Token, UID=GetUID, DeviceID=ApiKey] 
                            ]
                        )
                    ),
            tblAll = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
            tableHasRecords = Table.RowCount(tblAll) > 0,
            Result = if tableHasRecords then
                        Table.ExpandRecordColumn(tblAll,"Column1", Table.ColumnNames(Table.FromRecords(List.Select(Table.Column(tblAll,"Column1"), each _ <> "" and _ <> null))),Table.ColumnNames(Table.FromRecords(List.Select(Table.Column(tblAll,"Column1"), each _ <> "" and _ <> null))))
                     else
                        #table(Table.ColumnNames(tblAll), {})
        in
            Result,

    // Initial pagination parameters
    Offset = 0,
    Limit = 10000,
    PageSize = 10000,

    // Loop through pages to get all records
    AllPages = List.Generate(
                    () => [Result = Fetchjobs(Offset, Limit), Offset = Offset + PageSize],
                    each Table.RowCount([Result]) > 0,
                    each [Result = Fetchjobs([Offset], Limit), Offset = [Offset] + PageSize],
                    each [Result]
                ),

    // Combine all the pages into a single table
    tbljobs = Table.Combine(AllPages)//,

    // Change column types as needed
    //#"Changed Type" = Table.TransformColumnTypes(tbljobs,{{"StartedDate", type datetime}})
    tbljobs
in
    tbljobs//#"Changed Type"

我不会从表中得到任何结果。

那么可能是什么问题？

谢谢

powerbi powerquery powerbi-desktop
1个回答
0
投票

我的猜测是，服务器返回 JSON 结果，而不是明确声明 StartedDate 为 null，StartedDate 是从 JSON 对象中丢失/省略（其中为 null）。

因此，当 PowerQuery 将 JSON 转换为表并且在整个数据页中没有看到任何 StartedDate 属性时，生成的表没有 StartedDate 列！

尝试创建一个组合不同列名的表的函数，就像这样......

(Tables as list) as table =>
let
    #"Column names per table" = List.Transform(Tables, Table.ColumnNames),
    AllColumnNames = List.Distinct(List.Combine(#"Column names per table")),
    #"Missing column names per table" = List.Transform(#"Column names per table", each List.RemoveItems(AllColumnNames, _)),
    #"Tuples of table & missing column names" = List.Zip({Tables, #"Missing column names per table"}),
    #"Tables with all column names" = List.Transform(
        #"Tuples of table & missing column names",
        each List.Accumulate(
            _{1}, // Missing column names
            _{0}, // Table
            (tbl, cn) => Table.AddColumn(tbl, cn, each null)
        )
    ),
    Combined = Table.Combine(#"Tables with all column names")
in
    Combined

如果我是对的，并且如果您将其放入名为 

fTableCombineWithColumnsCheck
的单独查询中，那么您可以将 
tbljobs = Table.Combine(AllPages)
替换为 
tbljobs = fTableCombineWithColumnsCheck(AllPages)
，事情就会开始工作。

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