jsonobjectsnowflake-cloud-data-platformcase-sensitivelowercase

Making json keys lowercase Snowflake


I have a table that looks like

ID DATE FIRST_NAME H&P
12 2023-02-01 JESSICA 40
99 2023-02-03 MINA 98
12 2023-01-14 JACK 12

I've created another table containing these columns as columns by doing

SELECT ID, OBJECT_CONSTRUCT(*) as details
FROM MY_TABLE;
ID DETAILS
12 {"DATE":"2023-02-01", "FIRST_NAME":"JESSICA", "H&P":"40"}
99 {"DATE":"2023-02-03", "FIRST_NAME":"MINA", "H&P":"98"}
12 {"DATE":"2023-01-14", "FIRST_NAME":"JACK", "H&P":"12"}

Is there a way to modify the DETAILS column when using OBJECT_CONSTRUCT() so that the KEYS of the json are lowercase but the VALUES stay the same as they appear, so I could get something like

ID DETAILS
12 {"date":"2023-02-01", "first_name":"JESSICA", "h&p":"40"}
99 {"date":"2023-02-03", "first_name":"MINA", "h&p":"98"}
12 {"date":"2023-01-14", "first_name":"JACK", "h&p":"12"}

thanks! (I would like to do this without listing out the columns as my actual table has about 400 columns)


Solution

  • Keys could be listed explicitly as lower cased:

    CREATE OR REPLACE TABLE MY_TABLE(ID INT, DATE DATE, FIRST_NAME TEXT, "H&P" INT)
    AS
    SELECT 12,  '2023-02-01', 'JESSICA', 40 UNION
    SELECT 99,  '2023-02-03', 'MINA', 98 UNION
    SELECT 12,  '2023-01-14', 'JACK', 12;
    
    SELECT ID, OBJECT_CONSTRUCT('date', DATE, 
                                'fist_name', FIRST_NAME,
                                'h&p', "H&P") AS details
    FROM MY_TABLE;
    

    Output:

    ID DETAILS
    12 { "date": "2023-02-01", "fist_name": "JESSICA", "h&p": 40 }
    99 { "date": "2023-02-03", "fist_name": "MINA", "h&p": 98 }
    12 { "date": "2023-01-14", "fist_name": "JACK", "h&p": 12 }

    Using OBJECT constant syntax:

    SELECT ID, {'date': DATE, 
                'fist_name': FIRST_NAME,
                'h&p': "H&P"} AS details
    FROM MY_TABLE;
    

    EDIT:

    Is there a way to do it without explicitly listing the columns?

    Yes, one option requires flattening and building object second time which will reduce the performance:

    WITH cte AS (
      SELECT ID, OBJECT_CONSTRUCT(*) AS details
      FROM MY_TABLE
    )
    SELECT ID, OBJECT_AGG(LOWER(f.KEY), f.VALUE) AS details
    FROM cte
    ,LATERAL FLATTEN(INPUT => cte.details) AS f
    GROUP BY ID, SEQ;
    

    Output:

    enter image description here