Php CodeIgniter-更改子查询

我想将此子查询更改为CodeIgniter。如何使用rule CodeIgniter进行此查询

select *, 
            mahasiswa.nim AS id, (select count(id_absen) 
            from absen ABS 
            where ABS.nim = mahasiswa.nim 
            and tanggal >= DATE_SUB('$tgl_tutup_ujian', INTERVAL 3 MONTH) and tanggal <= '$tgl_tutup_ujian') AS jml_absen, 
            (select count(id_bayar) from pembayaran_iuran where ((bulan=MONTH(DATE_SUB('$tgl_tutup_ujian', INTERVAL 3 MONTH)) 
            and tahun=YEAR(DATE_SUB('$tgl_tutup_ujian', INTERVAL 3 MONTH)))
            or (bulan=MONTH(DATE_SUB('$tgl_tutup_ujian', INTERVAL 2 MONTH)) 
            and tahun=YEAR(DATE_SUB('$tgl_tutup_ujian', INTERVAL 2 MONTH))) 
            or (bulan=MONTH(DATE_SUB('$tgl_tutup_ujian', INTERVAL 1 MONTH)) 
            and tahun=YEAR(DATE_SUB('$tgl_tutup_ujian', INTERVAL 1 MONTH)))) 
            AND pembayaran_iuran.nim = mahasiswa.nim) 
            AS jml_bayar from mahasiswa 
            left join pendaftaran_ukt on pendaftaran_ukt.nim = mahasiswa.nim
            where nama like '$nama'

我试着这样做，但不起作用

$this->db->select('select *,mahasiswa.nim AS id, (select count(id_absen)');
        $this->db->from('absen ABS');
        $this->db->where('ABS.nim = mahasiswa.nim 
            and tanggal >= DATE_SUB('$tgl_tutup_ujian', INTERVAL 3 MONTH) and tanggal <= '$tgl_tutup_ujian') AS jml_absen');
        $this->db->select(' (select count(id_bayar)');
        $this->db->from('pembayaran_iuran');
        $this->db->where('((bulan=MONTH(DATE_SUB('$tgl_tutup_ujian', INTERVAL 3 MONTH)) 
            and tahun=YEAR(DATE_SUB('$tgl_tutup_ujian', INTERVAL 3 MONTH)))
            or (bulan=MONTH(DATE_SUB('$tgl_tutup_ujian', INTERVAL 2 MONTH)) 
            and tahun=YEAR(DATE_SUB('$tgl_tutup_ujian', INTERVAL 2 MONTH))) 
            or (bulan=MONTH(DATE_SUB('$tgl_tutup_ujian', INTERVAL 1 MONTH)) 
            and tahun=YEAR(DATE_SUB('$tgl_tutup_ujian', INTERVAL 1 MONTH)))) 
            AND pembayaran_iuran.nim = mahasiswa.nim)
            AS jml_bayar from mahasiswa ');
        $this->db->join('pendaftaran_ukt','pendaftaran_ukt.nim = mahasiswa.nim','left');
        $this->db->order_by('id_ukt','asc');
        $this->db->limit($limit, $offset);

我做错了什么？

CodeIgniter db库不支持子查询操作，您可以通过$this->db->query来管理查询操作

PS：您还可以安装子查询操作库，

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