加入2个表userid，fuserid in 1 with 2 fields SQL

Question

请告诉我如何提出请求。我需要从2个表中为[userid]和[fuserid]字段选择相同的值。

SELECT a.userid, b.fuserid FROM users, fusers WHERE a.userid=457281 AND b.fuserid=457281 

- 空白字段[userid] [fuserid]，虽然用户在表格中有2个值，而不是YET可用值

SELECT a.userid, b.fuserid FROM users RIGHT JOIN fusers ON a.userid=457281 AND b.fuserid=457281 

也会产生空字段[userid] [fuserid]

SELECT a.userid, b.fuserid FROM users LEFT JOIN fusers ON a.userid=457281 AND b.fuserid=457281 

- 发行垃圾邮箱，例如

      [userid][fuserid]
      [457281][NULL]
      [457281][NULL]
      [391419][NULL] 

- 一个不必要的额外字段

SELECT a.userid, b.fuserid FROM users JOIN fusers ON a.userid=457281 AND b.fuserid=457281 

- 空白字段

(SELECT a.userid FROM users WHERE a.userid=457281) UNION (SELECT b.fuserid FROM fusers WHERE b.fuserid=457281) 

- 返回值为457281的单个列，在本例中为[userid]

但我需要选择2个表相同的输入字段userid和fuserid显示在不同的列中，所以：

      [457281][457281] or
      [NULL][457281] or
      [457281][NULL]

Answer 1

很难弄清楚你想要什么，但根据你想要的结果，这是我的猜测。

  

[457281] [457281]或         [NULL] [457281]或         [457281] [NULL]

Select a.userid, b.fuserid 
   From users u 
   Full Outer Join fusers f on f.fuserid = u.userid
   Where f.fuserid = 457281 or u.userid = 457281