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Question

我有 tables with columns in the parentheses 就像这样：

Employee (Empno, Empname, City)
Project (Pno, Pname)
Part (Partno, Partname, Color)
Use (Pno, Partno)
Works (Empno, Pno)

我使用的是 ORACLE 11g 快捷版

我的查询：

SELECT *
  FROM (SELECT p.Pname AS Project_name
          FROM (SELECT COUNT(Color) AS colorPart, U.Pno, P.Color
                  FROM Part P
                  JOIN Use u
                    ON u.Partno = p.Partno
                   and p.Color = 'Red'
                 GROUP BY Color, Pno
                 ORDER BY colorPart DESC)
         WHERE rownum = 1) AS Final
  JOIN Project p
    ON Final.Pno = p.Pno;

这里出现错误：ORA-00933: SQL 命令未正确结束

Answer 1

您可以将当前查询重写为

SELECT p.Pname AS Project_name
  FROM (SELECT Pno
          FROM (SELECT Pno, COUNT(Color) AS ColorPart
                  FROM Part P
                  JOIN Use u
                    ON u.Partno = p.Partno
                   AND p.Color = 'Red'
                 GROUP BY Color, Pno
                 ORDER BY ColorPart DESC)
         WHERE rownum = 1) Final
  JOIN Project p
    ON Final.Pno = p.Pno

哪里

别名 Final 之前的
• AS 应该被删除，因为别名是 与其他一些 DBMS
不同，Oracle DB 中不允许使用子查询
• p.Pname 应该在最外层的查询中