Codeigniter parentheses in dynamic Active Record q

问题:

I'm producing a query like the following using ActiveRecord

SELECT * FROM (`foods`) WHERE `type` = 'fruits' AND 
       `tags` LIKE '%green%' OR `tags` LIKE '%blue%' OR `tags` LIKE '%red%'

The number of tags and values is unknown. Arrays are created dynamically. Below I added a possible array.

$tags = array (                 
        '0'     => 'green'.
        '1'     => 'blue',
        '2'     => 'red'
);  

Having an array of tags, I use the following loop to create the query I posted on top.

$this->db->where('type', $type); //var type is retrieved from input value

foreach($tags as $tag):         
     $this->db->or_like('tags', $tag);
endforeach; 

The issue: I need to add parentheses around the LIKE clauses like below:

SELECT * FROM (`foods`) WHERE `type` = 'fruits' AND 
      (`tags` LIKE '%green%' OR `tags` LIKE '%blue%' OR `tags` LIKE '%red%')

I know how to accomplish this if the content within the parentheses was static but the foreach loop throws me off..

回答1:

From the CI wiki:

The codeignighter ActiveRecord feature allows you to create SQL queries relatively simply and database-independant, however there isno specific support for including parenthesis in an SQL query.

For example when you want a where statement to come out simmilarly to the folowing:

WHERE (field1 = value || field2 = value) AND (field3 = value2 || field4 = value2) 

This can be worked around by feeding a string to the CI->db->where() function, in this case you will want to specifically escape your values.

See the following example:

$value=$this->db->escape($value);
$value2=$this->db->escape($value2);
$this->db->from('sometable');
$this->db->where("($field = $value || $field2 = $value)");
$this->db->where("($field3 = $value2 || $field4 = $value2)");
$this->db->get(); 

A simmilar workaround can be used for LIKE clauses:

$this->db->where("($field LIKE '%$value%' || $field2 LIKE '%$value%')");
$this->db->where("($field3 LIKE '%$value2%' || $field4 LIKE '%$value2%')"); 

回答2:

In the CI 3.0-dev you can add groups in query:

$this->db->select('id, title')
->group_start()
->or_like([ 'title' => $s, 'id' => $s ])
->group_end()                
->where([ 'b_del' => 0 ]);

Produces:

SELECT `id`, `title`, `venda1`
FROM `itens`
WHERE   
(
`title` LIKE '%a%' ESCAPE '!'
OR  `id` LIKE '%a%' ESCAPE '!'
 )
AND `b_del` =0 

回答3:

One of best feature to save your query when you applying multiple where or_where clauses.

$this->db->group_start();
$this->db->where();
$this->db->or_where();
$this->db->group_end();

Happy Coding. :)

回答4:

Going off of The Silencer's solution, I wrote a tiny function to help build like conditions

function make_like_conditions (array $fields, $query) {
    $likes = array();
    foreach ($fields as $field) {
        $likes[] = "$field LIKE '%$query%'";
    }
    return '('.implode(' || ', $likes).')';
}

You'd use it like this:

$search_fields = array(
    'field_1',
    'field_2',
    'field_3',
);
$query = "banana"
$like_conditions = make_like_conditions($search_fields, $query);
$this->db->from('sometable')
    ->where('field_0', 'foo')
    ->where($like_conditions)
    ->get()

回答5:

Just adding my successful solution:

$this->db->where("(table.field = $variable OR table.field IS NULL)");

回答6:

You can't add parentheses in ActiveRecord, but maybe WHERE IN is what you're looking for?

$names = array('Frank', 'Todd', 'James');
$this->db->where_in('username', $names);
// Produces: WHERE username IN ('Frank', 'Todd', 'James')

回答7:

$likes = array (                 
    '0'     => 'green'.
    '1'     => 'blue',
    '2'     => 'red'
);  
$where_like = "("; 
$or_counter = 1;
foreach($likes as $like_key => $like_val):
    $or_content = ($or_counter > 1) ?'OR': '';
    $newlikeval = $this->db->escape_like_str($like_val);
    $where_like .= $or_content." `$like_key` LIKE  '%$newlikeval%' ";
    $or_counter++;
endforeach;
$where_like .= ")";
$this->db->where($where_like);