如何將MySQL查詢轉換爲codeigniter活動記錄？

Question

我是codeigniter的新手，我想將下面的MySQL查詢轉換成Codeigniter Active Record Queries。

MySQL查詢：

select sevadar_id, sevadar_name from tbl_sevadarmaster where 
sevadar_designation = 6 and sevadar_id not in (SELECT p_id FROM 
`tbl_events` WHERE program_id = 27 and event_date = 2014-07-06 and p_id is not null) 

Answer 1

CI有真正好的文檔爲他們的整個API我強烈建議給他們一個快速閱讀。特別是關於你的問題，你應該看看Active Record文檔here和CodeIgniter query library，它會給你提示使用API​​生成更安全的查詢。這兩個鏈接共同包含您在CodeIgniter中構建查詢所需的所有API調用。

在最簡單的層次，你可以這樣做：

$query = $this->db->query('select sevadar_id, sevadar_name from tbl_sevadarmaster where sevadar_designation = 6 and sevadar_id not in (SELECT p_id FROM `tbl_events` WHERE program_id = 27 and event_date = 2014-07-06 and p_id is not null)'); 

但是你要使用查詢綁定（見query libraries頁面的最下方），以生產出更安全的查詢自動逃跑的數據，這裏是一個例子使用查詢綁定從API的那一頁：

$sql = "SELECT * FROM some_table WHERE id = ? AND status = ? AND author = ?"; 
$this->db->query($sql, array(3, 'live', 'Rick')); 

如果你使用活動記錄庫，你可以嘗試：

$this->db->select('p_id'); 
$this->db->from('tbl_events'); 
$this->db->where('program_id', 27); 
$this->db->where('event_date', '2014-07-06'); 
$this->db->where('p_id is not', null); 
$where_clause = $this->db->get_compiled_select(); 

$this->db->select('sevadar_id, sevadar_name'); 
$this->db->from('tbl_sevadarmaster'); 
$this->db->where('sevadar_designation', 6); 
$this->db->where("`sevadar_id` NOT IN ($where_clause)", NULL, FALSE);