Power BI - 处理不存在的参数并返回 table 中的有效参数数据

Question

我卡在了错误处理例程中。我有这个功能..

(LicenceNumber) =>
let
Source = 
Web.Page(Web.Contents("http://mbsweblist.fsco.gov.on.ca/ShowLicence.aspx?M" 
& Number.ToText(LicenceNumber) & "~")),
WebData = Source{1}[Data],
#"Extracted Text Before Delimiter" = Table.TransformColumns(WebData, 
{{"Column1", each Text.BeforeDelimiter(_, ":"), type text}}),
#"Removed Top Rows" = Table.Skip(#"Extracted Text Before Delimiter",1),
#"Transposed Table" = Table.Transpose(#"Removed Top Rows"),
#"Promoted Headers" = Table.PromoteHeaders(#"Transposed Table", 
[PromoteAllScalars=true])
in
#"Promoted Headers"

其中 returns 数据到 table

let
Source = {13000246..13000250},
#"Convert to Table" = Table.FromList(Source,Splitter.SplitByNothing(),{"Licence Number"}),
#"Changed Type" = Table.TransformColumnTypes(#"Convert to Table",{{"Licence Number", Int64.Type}}),
#"Get WebData" = Table.AddColumn(#"Changed Type", "WebData", each try WebData([Licence Number]) otherwise #table({},{})),
#"Combine WebData" = Table.Combine(#"Get WebData"[WebData]),
#"Changed Types" = Table.TransformColumnTypes(#"Combine WebData",{{"Agent/Broker Name", type text}, {"Licence #", type text}, {"Brokerage Name", type text}, {"Licence Class", type text}, {"Status", type text}, {"Issue Date", type date}, {"Expiry Date", type date}, {"Inactive Date", type date}})
in
#"Changed Types"

我正在尝试错误处理我在源中传递无效值的情况，假设源 = {13009995..13009999}，这是抛出错误 - "col X of table was not found"。我尝试使用以下错误处理逻辑，但它不起作用 ..

Empty = #table({{"Agent/Broker Name", type text}, {"Licence #", type text}, 
{"Brokerage Name", type text}, {"Licence Class", type text}, {"Status", type 
text}, {"Issue Date", type date}, {"Expiry Date", type date}, {"Inactive 
Date", type date}},{}),
Combine = Table.Combine({#"Get WebData"[WebData], Empty}),

我主要是一名业务分析师，无法修复此错误。请求帮助。用户 Olly 帮助我完成了主要查询

Answer 1

我建议创建一个空的 table 作为一个名为 EmptyTable 的单独查询，以便在您取回数据时匹配列。这是 M 代码：

let
    Empty =
    #table(
        {
        "Agent/Broker Name",
        "Licence #",
        "Brokerage Name",
        "Licence Class",
        "Status",
        "Issue Date",
        "Expiry Date",
        "Inactive Date"
        },
        {}
    )

in
    Empty

现在在您的 #"Get WebData" 步骤中，只需将 #table({},{}) 换成 EmptyTable。

#"Get WebData" =
Table.AddColumn(
    #"Changed Type",
    "WebData",
    each
        try WebData([Licence Number])
        otherwise EmptyTable
),

注意：当至少有一个有效的许可证号时，您的查询看起来工作正常。

Power BI - 处理不存在的参数并返回 table 中的有效参数数据

Power BI - handling non-existing arguments and returning data in table for valid arguments

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