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      FirstDiscreteByInvertedIndex
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      Contents

      FirstDiscreteByInvertedIndex

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      Article summary

      General: FirstDiscreteByInvertedIndex

      Creates a flag field where the first occurrence of each unique value in the specified field is set to 1 – but derived as if the table by in descending order of the sort field.

      Purpose

      Use this function to:
      • Reverse sort data before flagging first record that has a unique value
      • Flag the latest occurrence of a value in a Recordset

      Return Value

      PropertyValue
      FieldTypeInteger
      FieldSizeLow
      DataTypeDiscrete
      DataSizeByte


      Example Return Value: 0 , 1, null


      Parameters

      ParameterJSONDescription
      Table“targetTable”: “MyTableName”The target table on which the new field will be created
      Filter“dataset”: {DataSet_JSON}Optional.   If a filter is applied, records not in the filter recordset will be returned as null.
      Function"function":"firstdiscretebyinvertedindex"FirstDiscreteByInvertedIndex
      Distinct Key“p1”: “DistinctKeyFieldName”Required.
      Supports:
      • DataType: Must be a Discrete DataType from the target table - will not work with continuous fields.

      Once the data has been “reverse sorted” by the Sort Field, the first occurrence of each unique value of Distinct Key will be flagged.

      If a continuous field needs to be used, it may be possible to derive a discrete field from the continuous field using the CONCAT function. It may be necessary to apply a filter to reduce the number of discrete values. 

      Sort Field“p2”:"SortFieldName"Required.
      Supports:
      • DataType: Must be a Discrete DataType from the target table - will not work with continuous fields.
      Field used to determine the reverse sort order of the Recordset. The first occurrence of Distinct Key in the sorted Recordset will be flagged. 

      JSON Sample

      {
  "method": "BuildBakedField",
  "project": "D3",
  "targetTable": "transactions",
  "overwrite": true,
  "name": "FD_LastProduct_ByDate",
  "function": "firstdiscretebyinvertedindex",
  "p1": "product",
  "p2": "date"
}

      Usage Notes

      See Also:   

      • Engineering | Expression Field
      • FirstDiscrete (General Functions)
      • FirstDiscreteByIndex (General Functions)

      Example

      ExampleDetails
      Description
      Input
      • Table: = [transactions]
      • Filter: = [No Filter]
      • Function: = FirstDiscreteByInvertedIndex
      • Distinct Key:= product
      • Sort Field:= date
      • Name: =FD_LastProduct_ByDate
      Sample




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