如何从 Codeigniter 中的多个表中搜索数据？

Question

Hope you all good.

I am writing a query to get data from multiple tables with matched keyword, but always fail and server crashed. Please check my code below and let me know where i am wrong.

$this->db->select('c.name, c.email, c.comment, b.title, b.content')->from('blogs as b, blog_comments as c');
$this->db->group_start();
$this->db->or_like('c.name', $search);
$this->db->or_like('c.email', $search);
$this->db->or_like('c.comment', $search);
$this->db->or_like('b.title', $search);
$this->db->or_like('b.content', $search);
$this->db->group_end();
$this->db->limit(10);
$result = $this->db->get()->result_array();

echo $this->db->last_query();
echo '<pre>';
print_r($result);
echo '</pre>';

Any solution appreciated!

Answer 1

I rewrite your code with using JOIN instead of multiple FROM. Try it. I hope to helped for you.

$this->db->select('c.name, c.email, c.comment, b.title, b.content');
$this->db->from('blogs as b');
$this->db->join('blog_comments as c','b.blog_id = c.blog_id');
$this->db->group_start();
$this->db->like('c.name', $search);
$this->db->or_like('c.email', $search);
$this->db->or_like('c.comment', $search);
$this->db->or_like('b.title', $search);
$this->db->or_like('b.content', $search);
$this->db->group_end();
$this->db->limit(10);
$result = $this->db->get()->result_array();

echo $this->db->last_query();
echo '<pre>';
print_r($result);
echo '</pre>';

Answer 2

After lot of search from past few days finally found the solution for Codeigniter.

Now this function can search in your whole database without join.

function grep_db($db_name, $search_values = array())
{
        $table_fields = array();
        $cumulative_results = array();
        $result = $this->db->query("
        SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE
        FROM  `INFORMATION_SCHEMA`.`COLUMNS` 
        WHERE  `TABLE_SCHEMA` =  '{$db_name}'
        AND `DATA_TYPE` IN ('varchar', 'char', 'text')
        ")->result_array();

        foreach ($result  as $o) {
            $table_fields[$o['TABLE_NAME']][] = $o['COLUMN_NAME'];
        }
        foreach ($table_fields as $table_name => $fields) {
            $search_array = array();
            foreach ($fields as $field) {
                foreach ($search_values as $value) {
                    $search_array[] = " `{$field}` LIKE '%{$value}%' ";
                }
            }
            $search_string = implode(' OR ', $search_array);
            $query_string = "SELECT * FROM `{$table_name}` WHERE {$search_string}";
            $this->db->limit(10);
            $table_results = $this->db->query($query_string)->result_array();
            $cumulative_results = array_merge($cumulative_results, $table_results);
        }

        return $cumulative_results;
}

UPDATE

Search on specific table and columns of that table.

$search_tables = array(
    'blog_comments',
    'blog_comments' => array(
        'comment', 'email', 'name', 'blog_id'
    ),
    'blogs',
    'blogs' => array(
        'title', 'content', 'slug', 'blog_id'
    )
);

$result = $this->grep_db($this->db->database, [$search], $search_tables);

private function grep_db($db_name, $search_values = array(), $search_tables = array())
{
        $table_fields = array();
        $cumulative_results = array();

        $result = $this->db->query("
        SELECT TABLE_NAME, COLUMN_NAME, DATA_TYPE
        FROM  `INFORMATION_SCHEMA`.`COLUMNS` 
        WHERE  `TABLE_SCHEMA` =  '{$db_name}'
        AND `DATA_TYPE` IN ('varchar', 'char', 'text')
        ")->result_array();

        foreach ($result  as $o) {
            if (in_array($o['TABLE_NAME'], $search_tables)) {
                $table_fields[$o['TABLE_NAME']][] = $o['COLUMN_NAME'];
            }
        }

        foreach ($table_fields as $table_name => $fields) {
            $search_array = array();
            foreach ($fields as $field) {
                if (in_array($field, $search_tables[$table_name])) {
                    foreach ($search_values as $value) {
                        $search_array[] = " `{$field}` LIKE '%{$value}%' ";
                    }
                }
            }

            $search_string = implode(' OR ', $search_array);
            $search_column = implode(', ', $search_tables[$table_name]);
            $query_string = "SELECT {$search_column} FROM `{$table_name}` WHERE {$search_string}";
            $table_results = $this->db->query($query_string)->result_array();
            foreach ($table_results as $key => $result) {
                if (isset($result['blog_id'])) {
                    $table_results[$key]['link'] = $this->generate_url($result['blog_id']);
                }
                $table_results[$key]['table_name'] = $table_name;
            }
            $cumulative_results = array_merge($cumulative_results, $table_results);
        }
        return $cumulative_results;
}