SQL語法錯誤：“（”附近

Question

當我嘗試運行此查詢時：

select branch_no, max (avg_salary)
from (select allocatedto, avg (salary)
      from staff, worker
      where staff.staff_no = worker.staff_no
      group by allocatedto) 
      as branch_avg (branch_no, avg_salary);

我收到此錯誤：

Error: near "(": syntax error

Answer 1

select my_alias1,my_alias2 from (select col1,col2,...) as A (my_alias1,my_alias2)

上面的語法在SQL Server有效。

要為派生表中的列添加別名，您需要在派生表內部使用AS 。 嘗試這個

SELECT Max (avg_salary)
FROM   (SELECT allocatedto  AS branch_no,
               Avg (salary) AS avg_salary
        FROM   staff
               INNER JOIN worker
                       ON staff.staff_no = worker.staff_no
        GROUP  BY allocatedto) AS branch_avg;

還開始使用INNER JOIN而不是舊式逗號分隔的INNER JOIN

Answer 2

在SQLite中，子查詢上的AS子句無法分配列名（並且一開始就不需要）。

要重命名（子）查詢的輸出列，必須在SELECT子句中使用AS：

SELECT branch_no,
       max(avg_salary) AS avg_salary
FROM (...);

Answer 3

假設SQL Server的版本是2008 R2，

select branch_no, max (avg_salary)
from (select allocatedto, avg (salary)
      from staff, worker
      where staff.staff_no = worker.staff_no
      group by allocatedto) 
    as branch_avg (branch_no, avg_salary)
group by branch_no;