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  Public Ticket #1854443
ERROR- no data fetched (SQL Select CASE)
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  • jimmy started the conversation

    I have a custom table in the wordpress database. On the front end, I wish to display the table in a 'pivoted' type format, so I try to execute this query with wpdatatable:

    SELECT table.matchID,
    PROCESS_DATE,
    EVENT,
    TICKET,
    MAX(CASE WHEN table.Grappler IS NOT NULL THEN Grappler END) "person1",
    MIN(CASE WHEN table.Grappler IS NOT NULL THEN Grappler END) "person2"
    FROM table
    GROUP BY matchID, EVENT, TICKET, PROCESS_DATE

    This query works perfectly fine in MySQL and returns the output as expected. On wpdatatable however, I get:

    Error

    No data fetched! 
    If you are trying to save table for the first time, please enter some date before saving so table could be set accurately. 
    You can remove it later if you need empty table to start with.

    Rendered query: SELECT matchID, PROCESS_DATE, EVENT, TICKET, MAX "person1", MIN "person2" FROM table GROUP BY matchID, EVENT, TICKET, PROCESS_DATE LIMIT 10
    MySQL said: Unknown column 'MAX' in 'field list'


    Please assist. It seems to be ignoring my "CASE" statement.



  •  2,572
    Aleksandar replied

    Hello jimmy.

    Thank You for Your purchase.

    If your MySQL-query based wpDataTable doesn’t work correctly with server-side processing, probably this is happening because wpDataTables server has problems with parsing of the query and building new queries dynamically (rarely happens, but does sometimes). To avoid this please prepare a MySQL view (a stored query), which will return the data that you need, call it e.g. “view1” and then build a wpDataTabled based on a simple query like “SELECT * FROM view1″.

    Please note some this when working with the server-side processing feature:

    • Please do not use “LIMIT” in the SELECT statement. wpDataTables adds it automatically and it will be overridden.
    • Please do not use “ORDER BY” in the SELECT statement. wpDataTables has its own sorting engine so it makes no sense to use MySQL’s sorting, since it will be overridden. Also, server-side processing feature adds this part of statement automatically when users trigger the sorting on the front-end, and having it in initial statement may cause the table to crash.

    Please try this and let me know if this works.

    Best regards.

    Kind Regards, 

    Aleksandar Vuković
    [email protected]

    Rate my support

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  • jimmy replied

    Thanks Aleksander, creating a view worked, I just wished I would've been able to assemble the query entirely with wpdatatables.

  •  2,572
    Aleksandar replied

    Hello again jimmy.

    You are welcome. Glad that we solved the issue.

    If you have any more issues or questions feel free to open a new ticket, we will gladly help.

    As I said, unfortunately these things tend to happen sometimes. I am sorry if it causes any inconvenience.

    Best regards.

    Kind Regards, 

    Aleksandar Vuković
    [email protected]

    Rate my support

    wpDataTables: FAQ | Facebook | Twitter | InstagramFront-end and back-end demo | Docs

    Amelia: FAQ | Facebook | Twitter | InstagramAmelia demo sites | Docs | Discord Community

    You can try wpDataTables add-ons before purchasing on these sandbox sites:

    Powerful Filters | Gravity Forms Integration for wpDataTables | Formidable Forms Integration for wpDataTables | Master-Detail Tables