Manggaleh Laporan - Error Number: 1054

Assalamualaikum Warahmatullahi Wabarakatuh...
 
 
A Database Error Occurred
 
Error Number: 1054
 
Unknown column 'b.ppn' in 'field list'
 
select a.nama_pelanggan, a.alamat_pelanggan_1, a.kota, b.trx, c.total from (select x.*, y.name as kota from mu_pelanggan x JOIN mu_city y ON x.city_id=y.city_id) as a LEFT JOIN (select id_pelanggan, COUNT(*) trx from mu_transaksi GROUP BY id_pelanggan HAVING COUNT(id_pelanggan)) as b on a.id_pelanggan=b.id_pelanggan LEFT JOIN (SELECT a.*, b.id_pelanggan, sum(a.jumlah_jual*a.jumlah_satuan*a.harga_jual-a.diskon_jual-(b.ppn/100*(a.jumlah_jual*a.jumlah_satuan*a.harga_jual))) as total FROM `mu_transaksi_detail` a JOIN mu_transaksi b ON a.id_transaksi=b.id_transaksi GROUP BY b.id_pelanggan) as c on a.id_pelanggan=c.id_pelanggan where b.trx >=1 ORDER BY b.trx DESC
 
Filename: I:/xampp/htdocs/manggaleh/application/models/Model_laporan.php
 
Line Number: 70