CodeIgniter Active Records where in subquery

Try This

$this->db->where_in('a.transaction_link', "SELECT transaction_link from transaction WHERE transaction_type = '22'",false);

if you use false then it will remove single quotes from where_in condition

Sharmas Answer should do the job but if you wish fully supported Query Builder Methods you can try this

$strSubQuery = $this->db    ->select("transaction_link")    ->from("transaction")    ->where("transaction_type",22)    ->get_compiled_select();$query = $this->db    ->select("SUM(a.transaction_payment_amount)", false)    ->from('transaction_payment a')    ->where_in('a.transaction_link', $strSubQuery, false)    ->get();

You can change your code as following solution.

Changes your query

$this->db->select("SUM(a.transaction_payment_amount)");$this->db->from('transaction_payment a');$this->db->where("a.transaction_link IN (SELECT transaction_link from transaction WHERE transaction_type = '22')", null, false);//OR you can try other where condition if Sub query return null value than used this below query$this->db->where("IF(SELECT transaction_link from transaction WHERE transaction_type = '22',a.transaction_link IN (SELECT transaction_link from transaction WHERE transaction_type = '22'), NULL)", null, false);$query = $this->db->get();$result = $query->result();

I hope this will helps you. Thanks!