Using Lookup Values in Select Statements

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# Project Name - USING LOOKUP VALUES IN SELECT STATEMENTS

# Recipe URL - https://app.lingk.io/a/10932/tf/17911

# Description - # This recipe uses a file as a lookup table for values in a specific field.
                # To use this recipe, upload the file into the Local File connector for your Environment.

# example file (lookup.csv)
                # sfVal,sisVal
                # A,aa
                # B,bb
                # C,cc
                # D,dd

# Industry - Higher Ed
# Business Process - Graduate Reporting

# Systems - 
# Connectors - JSON
# Data Flows - Single Direction
# Connection Type - JSON

# Add Recipe notes / Change log information here!

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#

# CONNECTORS specify what data will be pulled into the in-memory database during processing

connectors:

# JSON Setup - https://help.lingk.io/en/articles/74-json-connector-reference

###### Start: LocalFile Connectors #######

-
    name: lookups
    type: localFileReader
    format: csvFormat
    properties:
      fileName: "lookup.csv"

###### End: LocalFile Connectors #######

###### Start: JSON Connectors #######      
-
    name: sourceDB
    type: JSON
    properties:
      jsonObject: |
        [ { "key":"A" },{ "key":"B" },{ "key":"C" } ]

###### End: JSON Connectors #######

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#  |_|  \___/|_|  |_| |_| |_|\__,_|\__|___/

# FORMATS specify how files should be processed as they are being read or written to

readFormats:
-
    name: csvFormat
    type: delimited
    properties:
      quoteAllFields: true
      delimiter: ','
      header: true

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#  |_____/ \__\__,_|\__\___|_| |_| |_|\___|_| |_|\__|___/

# STATEMENTS specify how the file should be processed while in memory      
statements:

#******************************************************************** D I S C L A I M E R ***********************************************************************************************
#                                                                                                                                                                                       * 
# Note that in an effort to keep recipes optimized for DPH (Data Processing Hours), print statements should be commented out after development has concluded for a recipe.              *
# For more information on DPH optimization, please visit the following help article - https://help.lingk.io/en/articles/212-minimizing-data-processing-hours-on-the-lingk-platform      *
#                                                                                                                                                                                       * 
#******************************************************************** D I S C L A I M E R ***********************************************************************************************

- statement: (dataCount) => select count(*) from lookups
  #- statement: print dataCount

# option #1 - using a join
  # A left outer join is a method of combining tables. The result includes unmatched rows from only the table that is specified before the LEFT OUTER JOIN clause.
  - statement: |
          (data) => 
              select
                 b.key,
                 a.sisVal lookupValue 
              from sourceDB b
                 LEFT OUTER JOIN lookups a ON a.sfVal = b.key
  #- statement: print data

# option #2 - using a subselect to handle lookups
  - statement: |
          (data) => 
              select
                 b.key,
                   (select first(a.sisVal) from lookups a where a.sfVal = b.key) lookupValue   
              from sourceDB b
  #- statement: print data

# Add more statements to convert, join, aggregrate, transform, and integrate your data