MySQL中的反透视表[重复]

Question

我想知道是否可以改变这个的输出：

User           Database            Select  Insert  Update  Delete  Create  References  Alter   Drop    
-------------  ------------------  ------  ------  ------  ------  ------  ----------  ------  --------
mysql.session  performance_schema  1       0       0       0       0       0           0       0       
mysql.sys      sys                 0       0       0       0       0       0           0       0  

进入这个：

Users               Privileges      performance_schema      sys
-----               ----------      ------------------      ---
mysql.session       Select                  1       
mysql.session       Insert                  0       
mysql.session       Update                  0       
mysql.session       Delete                  0       
mysql.session       Create                  0       
mysql.session       References              0       
mysql.session       Alter                   0       
mysql.session       Drop                    0       
mysql.sys           Select                                  0
mysql.sys           Insert                                  0
mysql.sys           Update                                  0
mysql.sys           Delete                                  0
mysql.sys           Create                                  0
mysql.sys           References                              0
mysql.sys           Alter                                   0
mysql.sys           Drop                                    0

我使用的查询是这样的：

SELECT 
  DISTINCT
  USER "User",
  db "Database",
  IF(Select_priv = 'Y', '1 ', '0') AS "Select",
  IF(Insert_priv = 'Y', '1 ', '0') AS "Insert",
  IF(Update_priv = 'Y', '1', '0') AS "Update",
  IF(Delete_priv = 'Y', '1', '0') AS "Delete",
  IF(Create_priv = 'Y', '1', '0') AS "Create",
  IF(References_priv = 'Y', '1', '0') AS "References",
  IF(Alter_priv = 'Y', '1', '0') AS "Alter",
  IF(Drop_priv = 'Y', '1', '0') AS "Drop"
 FROM
    mysql.db
 ORDER BY
    USER, Db;

任何帮助将不胜感激。提前致谢！！

Answer 1

这是一个“反透视”的示例：

(SELECT User AS Users, 'Select' AS Privileges, 1 AS PrivOrder, MAX(CASE db WHEN 'performance_schema' THEN Select_priv='Y' END) AS `performance_schema`, MAX(CASE db WHEN 'sys' THEN Select_priv='Y' END) AS `sys` FROM db GROUP BY User)
UNION
(SELECT User, 'Insert', 2, MAX(CASE db WHEN 'performance_schema' THEN Insert_priv='Y' END), MAX(CASE db WHEN 'sys' THEN Insert_priv='Y' END) FROM db GROUP BY User)
UNION
(SELECT User, 'Update', 3, MAX(CASE db WHEN 'performance_schema' THEN Update_priv='Y' END), MAX(CASE db WHEN 'sys' THEN Update_priv='Y' END) FROM db GROUP BY User)
UNION
(SELECT User, 'Delete', 4, MAX(CASE db WHEN 'performance_schema' THEN Delete_priv='Y' END), MAX(CASE db WHEN 'sys' THEN Delete_priv='Y' END) FROM db GROUP BY User)
UNION
(SELECT User, 'Create', 5, MAX(CASE db WHEN 'performance_schema' THEN Create_priv='Y' END), MAX(CASE db WHEN 'sys' THEN Create_priv='Y' END) FROM db GROUP BY User)
...
ORDER BY Users, PrivOrder;

抱歉，无法让透视或反透视查询根据找到的数据为每个架构自动定义列。必须在查询之前在查询开始读取数据之前设置列。