MySQL枢纽分析表，其中各列位于各自的列中

Question

I have a form in a WordPress site using the ARForms plugin which captures names, email and tel numbers, but in a stupid database layout.

I have a MYSQL WordPress table like this:

|id          |entry_value        |field_id        |entry_ID      |
|1           |John               |74              |1             |
|2           |Smith              |75              |1             |
|3           |555 1234           |76              |1             |
|4           |jsmith@mail.com    |77              |1             |
|5           |Sue                |74              |2             |
|6           |Brown              |75              |2             |
|7           |555 4321           |76              |2             |
|8           |sbrown@mail.com    |77              |2             |

I am using another plugin Export Report to try and query this table and get a report for all users who have filled out the form.

I want it in a format like this:

|ID           |Name              |Surname          |Email            |Telephone
|1            |John              |Smith            |jsmith@mail.com  |555 1234
|2            |Sue               |Brown            |sbrown@mail.com  |555 4321

I have tried the following from looking at a few examples but I keep getting NULL's returned. I need to filter it out somehow and only pivot where there are values. NOTE: There are 2 extra fields compared to the example above, InterestedIn and Province:

create view users_subscribed as (
  select 
    a.entry_id,
    a.field_id,
    case when field_id = '74' then entry_value end as FirstName,
    case when field_id = '75' then entry_value end as LastName,
    case when  field_id = '76' then entry_value end as Email,
    case when  field_id = '78' then entry_value end as Phone,
    case when  field_id = '79' then entry_value end as InterestedIn,
    case when  field_id = '81' then entry_value end as Province
  from ch_arf_entry_values a
);

create view users_subscribed_extended_pivot as (
  select
    entry_id as ID,
    FirstName,
    LastName,
    Email, 
    Phone,
    InterestedIn,
    Province
  from users_subscribed
  group by entry_id
);


SELECT * FROM users_subscribed_extended_pivot ;

Can anyone please assist...

Answer 1

you are missing, GROUP BY and MAX aggregate function

you don't need two views, you can do it in one view

  select 
    a.entry_id,
    MAX(case when field_id = 74 then entry_value end) as FirstName,
    MAX(case when field_id = 75 then entry_value end) as LastName,
    MAX(case when  field_id = 76 then entry_value end) as Email,
    MAX(case when  field_id = 78 then entry_value end) as Phone,
    MAX(case when  field_id = 79 then entry_value end) as InterestedIn,
    MAX(case when  field_id = 81 then entry_value end) as Province
  from ch_arf_entry_values a
  GROUP BY a.entry_id