Question

我正在学习M（Power Query Language）。我想使用M来解析REST API中的JSON。例如，可以使用Stack Overflow REST API。我可以看到如何使用say

深入研究一个简单的JSON字符串

let
    Source = Json.Document("{ ""glossary"": { ""title"": ""example glossary"", ""GlossDiv"": { ""title"": ""S"", ""GlossList"": { ""GlossEntry"":
        { ""ID"": ""SGML"", ""SortAs"": ""SGML"", ""GlossTerm"": ""Standard Generalized Markup Language"", ""Acronym"": ""SGML"",
          ""Abbrev"": ""ISO 8879:1986"", ""GlossDef"": { ""para"": ""A meta-markup language, used to create markup languages such as DocBook."",
          ""GlossSeeAlso"": [""GML"", ""XML""] }, ""GlossSee"": ""markup"" } } } } }"),
    glossary = Source[glossary],
    GlossDiv = glossary[GlossDiv],
    GlossList = GlossDiv[GlossList],
    GlossEntry = GlossList[GlossEntry],
    ConvertedToTable = Record.ToTable(GlossEntry)
in
    ConvertedToTable

但是当我有一个列表从中我想要钻取并获取子属性然后我想返回所有这些像SQL UNION查询时会发生什么。实际上它更像是For Each类型的查询。

所以这是我的非工作查询没有联合，但不幸的是将第二条记录粘贴到一边

let
    Source = "{""items"":["
       {""tags"":[""vba"",""permissions""],""owner"":
             {""reputation"":49,""user_id"":9073241,""user_type"":""registered"",""accept_rate"":86,""display_name"":""Kam""},
        ""is_answered"":false,""view_count"":4,""answer_count"":0,""score"":0,""question_id"":48229549},
       {""tags"":[""excel"",""vba"",""excel-vba""],""owner"":
             {""reputation"":18,""user_id"":9057704,""user_type"":""registered"",""accept_rate"":29,""display_name"":""Gregory""},
        ""is_answered"":false,""view_count"":6,""answer_count"":0,""score"":0,""question_id"":48229590}
       ]}",
    #"Parsed JSON" = Json.Document(Source),
    items = #"Parsed JSON"[items],
    item0 = items{0},
    owner0 = item0[owner],
    item1 = items{1},
    owner1 = item1[owner],
    #"Converted to Table" = Table.Combine( {Record.ToTable(owner0), Record.ToTable(owner1) })
in
    #"Converted to Table"

我真正的目标是输出但不限于2条记录，而是列表中的所有记录。（上面的示例源已经从此REST API StackOverflow questions tagged VBA）

简化

reputation  user_id user_type   accept_rate display_name
49          9073241 registered  86          Kam
18          9057704 registered  29          Gregory

Answer 1

我认为您希望在尝试组合它们之前调整表格。例如，尝试此查询。

let
    Source1 = Json.Document("{""tags"":[""vba"",""permissions""],""owner"":
             {""reputation"":49,""user_id"":9073241,""user_type"":""registered"",""accept_rate"":86,""display_name"":""Kam""},
        ""is_answered"":false,""view_count"":4,""answer_count"":0,""score"":0,""question_id"":48229549}"),
    Owner1 = Table.Pivot(Record.ToTable(Source1[owner]), List.Distinct(Record.ToTable(Source1[owner])[Name]), "Name", "Value"),
    Source2 = Json.Document("{""tags"":[""excel"",""vba"",""excel-vba""],""owner"":
             {""reputation"":18,""user_id"":9057704,""user_type"":""registered"",""accept_rate"":29,""display_name"":""Gregory""},
        ""is_answered"":false,""view_count"":6,""answer_count"":0,""score"":0,""question_id"":48229590}"),
    Owner2 = Table.Pivot(Record.ToTable(Source2[owner]), List.Distinct(Record.ToTable(Source2[owner])[Name]), "Name", "Value"),
    #"Appended Query" = Table.Combine({Owner1, Owner2})
in
    #"Appended Query"

如果您只想扩展所有所有者，请尝试更类似的查询：

let
    Source = "{""items"":[{""tags"":[""vba"",""permissions""],""owner"":{""reputation"":49,""user_id"":9073241,""user_type"":""registered"",""accept_rate"":86,""display_name"":""Kam""},""is_answered"":false,""view_count"":4,""answer_count"":0,""score"":0,""question_id"":48229549},{""tags"":[""excel"",""vba"",""excel-vba""],""owner"":{""reputation"":18,""user_id"":9057704,""user_type"":""registered"",""accept_rate"":29,""display_name"":""Gregory""},""is_answered"":false,""view_count"":6,""answer_count"":0,""score"":0,""question_id"":48229590}]}",
    #"Parsed JSON" = Json.Document(Source),
    items = #"Parsed JSON"[items],
    #"Converted to Table" = Table.FromList(items, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Expanded Column1" = Table.ExpandRecordColumn(#"Converted to Table", "Column1", {"owner"}, {"owner"}),
    #"Expanded owner" = Table.ExpandRecordColumn(#"Expanded Column1", "owner", {"reputation", "user_id", "user_type", "display_name"}, {"reputation", "user_id", "user_type", "display_name"})
in
    #"Expanded owner"

（M）Power Query是否具有表联合？

1 个答案: