为包含子查询的连接起别名的正确语法是什么？

Question

我正在尝试为具有子查询的 JOIN 设置别名。

RIGHT OUTER JOIN
    (
     SELECT   FieldA, FieldB
     FROM Table1
     JOIN Table2
     ON Table1.WellId = Table2.WellId
    ) AS wi
        AS MProd

ON Units.RS_Unit_Name = RTRIM(wi.RS_POOL) + '-' + wi.RS_Field

'AS' 附近的语法不正确...

wi 是别名 FieldA & FieldB；如何为 RIGHT OUTER JOIN 设置别名？

我原来的代码是：

RIGHT OUTER JOIN TABLE1
        AS MProd

ON Units.RS_Unit_Name = RTRIM(wi.RS_POOL) + '-' + wi.RS_Field

效果很好。我用我在代码示例中所做的子查询替换了 TABLE1。我似乎无法弄清楚将 MProd 设置为别名的正确语法。

Answer 1

问题出在这行代码：

 AS wi AS MProd

这是无效的语法。它可以是AS wi 或AS MProd，但不是 AS wi AS MProd。

这是有效的：

RIGHT OUTER JOIN 
( 
  SELECT FieldA, FieldB 
  FROM   Table1 
  JOIN   Table2 ON Table1.WellId = Table2.WellId 
) AS MProd
ON Units.RS_Unit_Name = RTRIM(MProd.RS_POOL) + '-' + MProd.RS_Field ...

也是这样：

RIGHT OUTER JOIN 
( 
  SELECT FieldA, FieldB 
  FROM   Table1 
  JOIN   Table2 ON Table1.WellId = Table2.WellId 
) AS wi
ON Units.RS_Unit_Name = RTRIM(wi.RS_POOL) + '-' + wi.RS_Field ...