为操作'；非法混合排序规则='； - Illegal mix of collations for operation '='

Illegal mix of collations for operation '='

我想从表"invoice_data"中选择数据，其中公司名称的值将通过电子邮件值从表"crm_accounts"中选择。我收到了类似的错误

操作'='的排序规则（utf8_unicode_ci，IMPLICIT）和（utf8-general_ci，IMPLICT）的非法混合

这是我的型号代码：

public function view_invoice($email)
    {
        $this->db->select('invoice_data.*, crm_accounts.company');
        $this->db->from('invoice_data');
        $this->db->join('crm_accounts', 'invoice_data.cname = crm_accounts.company', 'inner');
        $this->db->where('crm_accounts.email', $email);
        $query = $this->db->get();
        return $query->result_array();
    }

试试这个；

public function view_invoice($email)
{
    $this->db->select('invoice_data.*, crm_accounts.company');
    $this->db->from('invoice_data');
    $this->db->join('crm_accounts', 'invoice_data.cname = crm_accounts.company COLLATE utf8_unicode_ci', 'inner');
    $this->db->where('crm_accounts.email', $email);
    $query = $this->db->get();
    return $query->result_array();
}