將mysql where_in查詢更改為codeigniters活動記錄

Question

是否可以糾正此查詢

`$sql = '
    SELECT *
    FROM employers
    LEFT JOIN jobwall ON jobwall.employers_employer_id = employers.employer_id
    WHERE employers.employer_id
    IN (SELECT employers_employer_id FROM jobwall)
';

$this->db->query($sql);`

作為代碼記錄器中的活動記錄

Answer 1

我同意Joe Stefanelli的觀點，對於普通聯接來說，不需要LEFT JOIN和WHERE IN子查詢。 以下應該做您想要的：

$this->db->join('jobwall'
    , 'jobwall.employers_employer_id = employers.employer_id');
$this->db->get('employers');

僅當您想讓所有雇主（無論他們是否在工作表中）都需要使用LEFT JOIN。

Answer 2

我在找一樣的東西。 然后得到適當的答案。

$this->db->select('employers_employer_id');
$this->db->from('jobwall');

$subquery = $this->db->_compile_select();
$this->db->_reset_select();
$subquery = str_replace("\n"," ",$subquery);

$this->db->where_in('tag_page_id', $subquery, false); //false=if no escape for subquery 
$this->db->join('jobwall', 'jobwall.employers_employer_id = employers.employer_id','left');
$this->db->get('employers');