Question

我有两张桌子。我写了这个查询，但没有显示表格结果怎么写完美查询显示表结果？

  Taccess
 id   userid  groupid    accesstype
  1     2       1           1
  2     4       1           1

  Tgroup
   grugroupid       groupbname     userid  
       1               group-1       1
       2               group-2       2
       3               group-3       3
       4               group-4       4

我需要userid = 1的结果我想显示所有groupid然后显示accesstype userid = 1

  grugroupid         groupbname       accesstype
       1               group-1            1
       2               group-2            null  
       3               group-3            null
       4               group-4            null

     select grugroupid         , 
           userid ,groupbname     ,       
          (select AccessType from Access where   UserID=2 ) as dd,           
                 from  TLab_Info  
      union 
       select   id   userid  groupid    accesstype
          from   TLab_Access

Answer 1

def method2(): Unit = {
  val _ = method1()
}

结果：

SELECT g.grugroupid,g.groupbname,a.accesstype
FROM Tgroup g LEFT JOIN
     Taccess a on g.grugroupid=a.groupid
WHERE (a.accesstype IS NULL) OR (a.accesstype=1)
GROUP BY g.grugroupid,g.groupbname,a.accesstype

请参阅SQL Fiddle中的结果。

Answer 2

Raging Bull已发布的其他变体

SELECT DISTINCT 
       g.grugroupid,
       g.groupbname,
       a.accesstype
FROM   Tgroup g LEFT JOIN
       Taccess a ON g.grugroupid = a.groupid
WHERE COALESCE(a.accesstype,1) = 1

测试在这里SQL Fiddle

如何在两个表上编写完整的连接操作查询？

2 个答案: