如何在Codeigniter查询构建器中使用“ UNION”？

编程问答 2022-06-13

问题描述

我正在使用codeigniter query-builder运行查询：

   $this->db->select('t_heatpad.heatpad_status,t_heatpad.idheatpad,t_heatpad.heatpad_firstname,t_heatpad.heatpad_lastname,t_heatpad.heatpad_address,t_heatpad.heatpad_phone,t_heatpad.heatpad_doc_firstname,t_heatpad.heatpad_doc_lastname,t_heatpad.heatpad_doc_npi,t_heatpad.heatpad_doc_phone,t_heatpad.heatpad_doc_fax,t_heatpad.heatpad_med_id,t_heatpad.heatpad_data_entered,t_heatpad.heatpad_global ');
   $this->db->from('t_heatpad');
   $subQuery4 = $this->db->get_compiled_select(); 

    
   $this->db->select('t_cgm_diabetic.cgmdiab_status,t_cgm_diabetic.idcgmdiab,t_cgm_diabetic.cgmdiab_firstname,t_cgm_diabetic.cgmdiab_lastname,t_cgm_diabetic.cgmdiab_address,t_cgm_diabetic.cgmdiab_phone,t_cgm_diabetic.cgmdiab_doc_firstname,t_cgm_diabetic.cgmdiab_doc_lastname,t_cgm_diabetic.cgmdiab_doc_npi,t_cgm_diabetic.cgmdiab_doc_phone,t_cgm_diabetic.cgmdiab_doc_fax,t_cgm_diabetic.cgmdiab_medicare,t_cgm_diabetic.cgmdiab_date_entered,t_cgm_diabetic.cgmdiab_global ');
  $this->db->from('t_cgm_diabetic');
  $subQuery5 = $this->db->get_compiled_select();

现在，我要在$ subQuery4和$ subQuery5上加入并集。
这种方法对我来说很好：

$this->db->query("select * from ($subQuery4 UNION $subQuery5 ) as unionTable");

但是我想用这种格式：

 $this->db->select('*');    
 $this->db->from("($subQuery4 UNION $subQuery5 )");
 $this->db->get();

解决方法

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