php 如何在我的查询 CODEIGNITER 中使用 DISTINCT
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/19509805/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
how to use DISTINCT here in my query CODEIGNITER
提问by Ezekiel Blanco
$q = $this->db->select('
books.title,
reserved_books.id,
reserved_books.isbn,
reserved_books.price,
reserved_books.item_sold,
reserved_books.date_sold,
reserved_books.total_amount
')
->from('reserved_books')
->join('books','reserved_books.isbn= books.isbn')
->limit($limit,$offset);
how can i use distinct here in my query? reserved_books.isbn is the unique one.
我如何在我的查询中使用 distinct ？reserved_books.isbn 是独一无二的。
回答by Mandip Darji
Try Below:
试试下面：
$this->db->distinct();
but Distinct will not always work. You should add ->group_by("name_of_the_column_which_needs_to_be unique");
但 Distinct 并不总是有效。你应该添加 ->group_by("name_of_the_column_which_needs_to_be unique");
$this->db->group_by('column_name');
回答by Zia
You don't need any join
你不需要任何加入
$query=$this->db->distinct()->select('table_attribute')->where('condition')->get('table_name');
return $query->result();
回答by Moeed Farooqui
回答by Muhammad Raheel
Here is a way to do this
这是一种方法来做到这一点
$select = array(
'books.title',
'reserved_books.id',
'DISTINCT reserved_books.isbn',
'reserved_books.price',
'reserved_books.item_sold',
'reserved_books.date_sold',
'reserved_books.total_amount'
);
$q = $this->db
->select($select)
->from('reserved_books')
->join('books','reserved_books.isbn= books.isbn')
->group_by('reserved_books.isbn')
->limit($limit,$offset);
回答by Vikas Kumar
Here is best way to remove duplicate entry.
这是删除重复条目的最佳方法。
$query = $this->db->select("inf.id, inf.sku, inf.fab_id, inf.sku, inf.amount, inf.min_length, inf.num_of_pieces, inf.width ,inf.type")
->join("retailcat","retailcat.sku=SUBSTRING(inf.sku,1,19) AND retailcat.category=218","INNER")
->distinct()
->get("input_factor inf");
