PostgreSQL 9.3：交叉表查询中的无效计数

Question

我有以下数据要显示到数据透视表 table 中：

下面是table Employee包含员工详细信息：

          Employee_Number              Employee_Role                Group_Name
          --------------------------------------------------------------------
           EMP101                      C# Developer                  Group_1               
           EMP102                      ASP Developer                 Group_1               
           EMP103                      SQL Developer                 Group_2               
           EMP104                      PLSQL Developer               Group_2               
           EMP101                      Java Developer                                           
           EMP102                      Web Developer                                            
           EMP101                      DBA                                             
           EMP105                      DBA                                             
           EMP106                      SQL Developer                 Group_3               
           EMP107                      Oracle Developer              Group_3               
           EMP101                      Oracle Developer              Group_3               
           EMP108                      JSP                           Group_4               
           EMP108                      JS                            Group_5               
           EMP101                      C# Developer                  Group_1               
           EMP101                      C# Developer                  Group_1               
           EMP101                      C# Developer                  Group_1               
           EMP101                      C# Developer                  Group_1

我想将输出显示到枢轴 table 中，如下所示：

Employee_Number     TotalRoles      TotalGroups       Available     Others     Group_1     Group_2      Group_3      Group_4      Group_5
------------------------------------------------------------------------------------------------------------------------------------------
   EMP101               8                5                2           6           5           0            1             0           0
   EMP102               2                5                1           1           1           0            0             0           0
   EMP103               1                5                1           0           0           1            0             0           0   
   EMP104               1                5                1           0           0           1            0             0           0
   .......
   .......

我正在使用这个脚本：

SELECT * FROM crosstab(
      $$SELECT grp.*, e.group_name
     , CASE WHEN e.employee_number IS NULL THEN 0 ELSE 1 END AS val
    FROM  (
       SELECT employee_number
    , count(employee_role)::int            AS total_roles
    , (SELECT count(DISTINCT group_name)::int
       FROM   employee
       WHERE  group_name <> '')            AS total_groups
    , count(group_name <> '' OR NULL)::INT AS available                    
    , count(group_name =  '' OR NULL)::int AS others
       FROM   employee
       GROUP  BY employee_number
       ) grp
    LEFT   JOIN employee e ON e.employee_number = grp.employee_number
          AND e.group_name <> ''         
    ORDER  BY grp.employee_number, e.group_name$$
     ,$$VALUES ('Group_1'),('Group_2'),('Group_3'),('Group_4'),('Group_5')$$
   ) AS ct (employee_number text
      , total_roles  int
      , total_groups int
      , available    int
      , others       int
      , Group_1    int
      , Group_2    int
      , Group_3    int
      , Group_4    int
      , Group_5    int);

但是在 EMP101 的输出中出现错误 Available 它必须为 2 因为他是在 group_1 和 group_3 中可用。但是为此得到一个错误。

Answer 1

我看到两个问题： 1) count(group_name <> '' OR NULL) 将计算每个非空白的 group_name 的出现次数，即当有重复时，您将重复计算值。 2) 您没有对组计数进行分组 - 交叉表函数不会为您聚合，因此当一名员工多次属于一个组时，您会得到不正确的组计数。下面的查询有不同的计算可用方式，并对计数进行分组。你会得到缺失值的空值，但你之前得到它们:-)

SELECT * FROM crosstab(
      $$SELECT grp.*, e.group_name
     ,  val
    FROM  (
       SELECT employee_number
    , count(employee_role)::int            AS total_roles
    , (SELECT count(DISTINCT group_name)::int
       FROM   employee
       WHERE  group_name <> '')            AS total_groups

    , (count(distinct group_name) - count(distinct group_name =  '' OR NULL))::int AS available   

    , count(group_name =  '' OR NULL)::int AS others
       FROM   employee
       GROUP  BY employee_number
       ) grp
    LEFT   JOIN 
    (select employee_number,group_name,count(*) as val from employee group by employee_number,group_name) e
      ON e.employee_number = grp.employee_number

    ORDER  BY grp.employee_number, e.group_name$$
     ,$$VALUES ('Group_1'),('Group_2'),('Group_3'),('Group_4'),('Group_5')$$
   ) AS ct (employee_number text
      , total_roles  int
      , total_groups int
      , available    int
      , others       int
      , Group_1    int
      , Group_2    int
      , Group_3    int
      , Group_4    int
      , Group_5    int);

PostgreSQL 9.3：交叉表查询中的无效计数

PostgreSQL 9.3: Invalid count within crosstab query

postgresql

postgresql-9.3

crosstab