Using DISTINCT in a CakePHP find function

Question

I am writing a CakePHP 1.2 app. I have a list of people that I want the user to be able to filter on different fields. For each filterable field, I have a drop down list.

Answer 1

I know it is a question for CakePHP 1.2, but I was searching for that too with CakePHP version 3. And in this version there is a method to form the Query into a distinct one:

$first_names = $this->Persons->find(
    'list',
    [
        'fields'=> ['name']
    ]
)
  ->distinct();
;

This will generate a sql query like this:

SELECT DISTINCT Persons.name AS `Persons__name` FROM persons Persons

But the distinct method is a bit mightier than just inserting DISTINCT in the query.

If you want to just distinct the result on one field, so just throwing away a row with a duplicated name, you can also use the distinct method with an array of the fields as parameter:

$first_names = $this->Persons->find(
    'list',
    [
        'fields'=> ['id', 'name'] //it also works if the field isn't in the selection
    ]
)
  ->distinct(['name']); //when you use more tables in the query, use: 'Persons.name'
;

This will general a sql query like this (for sure it is a group query):

SELECT DISTINCT
    Persons.id AS `Persons__id`, Persons.name AS `Persons__name`
FROM persons Persons
GROUP BY name #respectively Persons.name

Hope I will help some for CakePHP 3. :)