I have submissions of a form from a web page records in a database.
the table has the following schema

submit_time form_name field_name field_value field_order file

the form has 5 fields, each form submission results in 5 rows in the previous table, one row per field. the following is an example of 5 rows created after a submission.

    submit_time       form_name     field_name  field_value field_order file
    1427715050.2890 Contact form 1  your-name       Jung            0   NULL
    1427715050.2890 Contact form 1  your-email      [email protected]  1   NULL
    1427715050.2890 Contact form 1  your-subject    Jung maybe :)   2   NULL
    1427715050.2890 Contact form 1  your-message    Jung :D         3   NULL
    1427715050.2890 Contact form 1  Submitted Login Mohammad    9999    NULL

I want the data to be written in another table in another database the new table has the following schema:

Name email subject message Login

What I tried
I thought about writing a trigger like the following:

    TRIGGER copy_data
    # check if submission entry exists in table B

    # NO :
        # INSERT the data in the corresponding column 

    # YES:
        # UPDATE the data in the corresponding column  


but I can't insert NULL values in the second table.

what can I do in such situation ?

Note: I can't guarantee the order of the rows in Table A ( which field will be inserted first is something I can't control)

  • what happen if the same form (contact form 1) are filled from two distinct users at the same time (i.e. 1427715050.2890)? Maybe it is a rare event, but could it happen?
    – Giovanni
    Mar 31, 2015 at 13:05
  • A very long shot. Mar 31, 2015 at 13:08
  • :-) However I think it is better to have an unique id associated to a form submission, and to have all rows of the first table inserted into unique transaction.
    – Giovanni
    Mar 31, 2015 at 13:22
  • The insertion into table A is being done by a WordPress plug in, the form is online. Mar 31, 2015 at 13:23
  • So, I guess that plug in is handling that case somehow, maybe by just discarding the second user I have no idea. But you are absolutely right. Mar 31, 2015 at 13:25

1 Answer 1


The TRIGGER can be simplified down to


It is not proper to have "redundant" data in a database. Why can't you just leave it in the original table? When you need it, do a JOIN.

  • I agree, it is not proper. But the insertion is done through a WordPress plug in which I can't control it is behavior. Would this solution work? It won't insert null values? Apr 1, 2015 at 7:07
  • I'm sorry, I lose patience with 3rd party packages that get in the way. You have 2 packages -- WP and a plugin. Complain to them. Meanwhile, you are having to become an expert in MySQL just to figure out how to work around their limitations.
    – Rick James
    Apr 1, 2015 at 17:51
  • And since I am not expert enough I turned to the community here, I just need to select a column and make it a row in another table. How remains a mystery :-D Apr 1, 2015 at 17:53

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