带有多个具有数据列的PostgreSQL枢轴

Question

我想在表格下方旋转/交叉表

我在PostgreSQL中尝试了以下查询，但给出错误ERROR：无效的返回类型 详细信息：查询指定的返回元组有6列，但交叉表返回5

 SELECT * FROM crosstab(
'select Key,status,v_text,v_number,v_dob from table 
    where type = ''First_Name'' or type = ''Last_Name''  or type = ''DOB'' or type = ''Contact'' order by 1',
'select distinct type  from table where type = ''First_Name'' or type = ''Last_Name'' or type = ''DOB'' or type = ''Contact'' order by 1')
 AS ct( Key int, First_Name text,   Last_Name  text, DOB date, Contact int);

所需的输出如下所示，其中所有类型都有值。在pgsql中可以吗

Answer 1

我建议条件聚合。这是标准的SQL语法，并且比诸如crosstab之类的特定于供应商的实现要灵活得多：

select
    key,
    status,
    max(v_text)   filter(where type = 'FistName') first_name,
    max(v_text)   filter(where type = 'LastName') last_name,
    max(v_date)   filter(where type = 'DOB')      dob,
    max(v_number) filter(where type = 'Contact') contact
from mytable
group by key, status

Answer 2

您可以按照以下步骤进行操作-

select  key,
  status,
  max(case when type = 'First name' then v_text end) As first_name,        
  max(case when type = 'Last name' then v_text end) As last_name, 
  max(case when type = 'DOB' then v_date end) As DOB,
  max(case when type = 'Contact' then v_number end) As Contact 
from mytable 
group by key, status;