选择列作为行并对结果进行分组

Question

我在查询工作期间遇到了困难 我有一个看起来像这样的客户数据库

客户

• ID
• CreatedTime

字段

• 名称
• UniqID

FieldsContent

• FieldUniqID
• 值
• 客户id

最后我想制作一张看起来像这样的桌子

• Customer.ID作为CustomerID
• Field.Name as FirstName
• Field.Name作为LastName
• Field.Name as Email
• Field.Name as Phone
• Customer.Created as Created

希望你能帮我找到怎么做，

我用php编写了它，你可以看到：

$this->db->query('SET SESSION group_concat_max_len=10000000');
            $q = $this->db->select("GROUP_CONCAT(fieldsContent.Content SEPARATOR '|*|') AS Content,
                                    GROUP_CONCAT(fieldsContent.FieldID SEPARATOR '|*|') AS FieldID,
                                    customers.Created,
                                    customers.ID",false)
                          ->from('customers')
                          ->join('fieldsContent','fieldsContent.TypeID = customers.ID','left outer')
                          ->where(array('fieldsContent.TypeName' => 'customers',
                                        'customers.ID' => $id))
                          ->group_by('fieldsContent.TypeID')
                          ->order_by('customers.Created','DESC')
                          ->get();
            foreach($q->result() as $d){
                $field = explode('|*|',$d->FieldID);
                $content = explode('|*|',$d->Content);
                foreach($field as $k => $FieldID){   
                    $dd[$FieldID] = $content[$k];
                }
            }

但我只需要sql而不使用php

Answer 1

可能是以下情况？

SET SESSION group_concat_max_len=10000000;
CREATE VIEW <view_name> AS 
        ( 
                  SELECT    group_concat(fieldscontent.content separator '|*|') AS content,
                            group_concat(fieldscontent.fieldid separator '|*|') AS fieldid,
                            customers.created
                  FROM      customers 
                  LEFT JOIN fieldscontent
                  ON        fieldscontent.typeid = customers.id
                  GROUP BY  fieldscontent.typeid
                  ORDER BY  customers.created DESC
        )

然后你可以过滤视图！