MySQL 使用codeigniter的活动记录语法增加mysql数据库的字段
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Increment field of mysql database using codeigniter's active record syntax
提问by Casey Flynn
I have the following php-codeigniter script which attempts to increment a field of a record using active-record syntax:
我有以下 php-codeigniter 脚本，它尝试使用 active-record 语法增加记录的字段：
$data = array('votes' => '(votes + 1)');
$this->db->where('id', $post['identifier']);
$this->db->update('users', $data);
This produces the following SQL:
这将产生以下 SQL：
"UPDATEusersSETvotes= '(votes + 1)' WHEREid= '44'"
"UPDATE用户SET投票= '(votes + 1)' WHERE编号= '44'“
Which doesn't run, but this SQL does do what I'm looking for:
"UPDATEusersSETvotes= (votes + 1) WHEREid= '44'"` <--Note the lack of quotes around (votes + 1)
哪个没有运行，但是这个 SQL 确实做了我正在寻找的：
"UPDATE用户SET投票= (votes + 1) WHEREid = '44'"` <--注意周围缺少引号 (votes + 1)
Does anyone know how to implement this type of query with codeigniter's active record syntax?
有谁知道如何使用 codeigniter 的活动记录语法来实现这种类型的查询？
回答by Boban
You can do as given below:
您可以按照以下说明进行操作：
$this->db->where('id', $post['identifier']);
$this->db->set('votes', 'votes+1', FALSE);
$this->db->update('users');
The reason this works is because the third (optional) FALSE parameter tells CodeIgniter not to protect the generated query with backticks ('). This means that the generated SQL will be:UPDATE users SET votes= votes + 1 WHERE id= '44'
If you notice, the backticks are removed from '(votes+1)', which produces the desired effect of incrementing the votes attribute by 1.
这样做的原因是因为第三个（可选）FALSE 参数告诉 CodeIgniter 不要用反引号 ( ')保护生成的查询。这意味着生成的 SQL 将是：UPDATE users SET votes= votes + 1 WHERE id= '44'
如果您注意到，从 中删除了反引号'(votes+1)'，这会产生将 votes 属性增加 1 的预期效果。
回答by wanderer
$data = array('votes' => 'votes + 1');
foreach ($data as $key=>$val) {
$this->db->set($key, $val, FALSE);
}
$this->db->where('id', $post['identifier']);
$this->db->update('users', $data);
回答by Sani Kamal
You can do as given below:
您可以按照以下说明进行操作：
public function increament_product_count(){
$product_id=$this->input->post('product_id');
$this->db->where('id', $product_id);
$this->db->set('click_count', 'click_count+1', FALSE);
$this->db->update('tbl_product');
}
