MYSQL Select update query multiple joins error

Question

i am trying to update a variable row, in a variable table. This is my query:

// EDIT: removed double...

UPDATE `ec`.`category_id` AS `category_id`,`e`.`title` AS `title`,
    `r`.`first_name` AS `first_name`,
    `r`.`last_name` AS `last_name`,`r`.`email` AS `email`,
    `r`.`comment` AS `comment`,`r`.`amount` AS `amount`,
    `r`.`published` AS `published`,`r`.`transaction_id` AS `transaction_id`,
    `r`.`register_date` AS `register_date`,
max((case `f`.`id` when 1 then `v`.`field_value` else '' end)) AS `pand`,
max((case `f`.`id` when 52 then `v`.`field_value` else '' end)) AS `achternaam`,
max((case `f`.`id` when 53 then `v`.`field_value` else '' end)) AS `voornaam`,
max((case `f`.`id` when 20 then `v`.`field_value` else '' end)) AS `gebdat`,
max((case `f`.`id` when 32 then `v`.`field_value` else '' end)) AS `geslacht`,
max((case `f`.`id` when 31 then `v`.`field_value` else '' end)) AS `kleinkind`,
max((case `f`.`id` when 21 then `v`.`field_value` else '' end)) AS `straat`,
max((case `f`.`id` when 54 then `v`.`field_value` else '' end)) AS `postcode`,
max((case `f`.`id` when 55 then `v`.`field_value` else '' end)) AS `plaats`,
max((case `f`.`id` when 26 then `v`.`field_value` else '' end)) AS `telthuis`,
max((case `f`.`id` when 27 then `v`.`field_value` else '' end)) AS `telmir`,
max((case `f`.`id` when 28 then `v`.`field_value` else '' end)) AS `gsmdeelnemer`,
max((case `f`.`id` when 29 then `v`.`field_value` else '' end)) AS `gsmpapa`,
max((case `f`.`id` when 56 then `v`.`field_value` else '' end)) AS `gsmmama`,
max((case `f`.`id` when 30 then `v`.`field_value` else '' end)) AS `graad`,
max((case `f`.`id` when 88 then `v`.`field_value` else '' end)) AS `bestelling`,
max((case `f`.`id` when 34 then `v`.`field_value` else '' end)) AS `eigendom`,
max((case `f`.`id` when 57 then `v`.`field_value` else '' end)) AS `zodiac`,
max((case `f`.`id` when 42 then `v`.`field_value` else '' end)) AS `tshirt`,
max((case `f`.`id` when 39 then `v`.`field_value` else '' end)) AS `helpdag`,
max((case `f`.`id` when 40 then `v`.`field_value` else '' end)) AS `helpinfo`,
max((case `f`.`id` when 36 then `v`.`field_value` else '' end)) AS `vervoerjanee`,
max((case `f`.`id` when 37 then `v`.`field_value` else '' end)) AS `vervoerinfo`
from ((((`dat_eb_field_values` `v` join `dat_eb_registrants` `r` on((`v`.`registrant_id` = `r`.`id`)))
join `dat_eb_fields` `f` on((`v`.`field_id` = `f`.`id`)))
join `dat_eb_events` `e` on((`r`.`event_id` = `e`.`id`)))
join `dat_eb_event_categories` `ec` on((`ec`.`event_id` = `e`.`id`)))
where ((`ec`.`category_id` = 4) and (`e`.`published` = 1))
SET $rowname=$newvalue WHERE transaction_id=$transid

Normally this query uses SELECT as the first argument instead of UPDATE. The last line was also added by me. $rowname, $newvalue and $transid are all defined and it geives me the following error:

Not unique table/alias: 'first_name'.

Thanks in advance, Laurent

Answer 1

Problem is here

`r`.`first_name`,`r`.`first_name` AS `first_name`,

You have ambiguous aliases.

Answer 2

The syntax for UPDATE clause is something like this

UPDATE table JOIN table1 ON table.field = table1.field SET table.field2 = 'value' WHERE table.field3 = 'value2'

You don't provide any fields to select as UPDATE clause does not select anything. So, you should remove the fields from SELECT clause and add the WHERE pats after SET.

UPDATE 
((((`dat_eb_field_values` `v` join `dat_eb_registrants` `r` on((`v`.`registrant_id` = `r`.`id`)))
join `dat_eb_fields` `f` on((`v`.`field_id` = `f`.`id`)))
join `dat_eb_events` `e` on((`r`.`event_id` = `e`.`id`)))
join `dat_eb_event_categories` `ec` on((`ec`.`event_id` = `e`.`id`)))

SET $rowname=$newvalue

WHERE ((`ec`.`category_id` = 4) and (`e`.`published` = 1)) AND transaction_id=$transid