列「TRANSACTION_EVENT_ID」被指定爲「YY」

Question

多次我寫了一個這樣的查詢：

SELECT 
    YY.ACCOUNT_ID, 
    YY.TRANSACTION_EVENT_ID 
FROM 
    (SELECT * 
    FROM dbo.TRANSACTION TE 
    JOIN dbo.FUND_TRANSACTION FT 
    ON TE.TRANSACTION_EVENT_ID = FT.TRANSACTION_EVENT_ID 
    JOIN ACCOUNT A 
    ON FT.ACCOUNT_ID = A.ACCOUNT_ID) AS YY 

，並收到錯誤是這樣的：

指定的列「TRANSACTION_EVENT_ID」多次爲 'YY'

選中此：SQL The column 'Id' was specified multiple times

但是，問題沒有解決。我究竟做錯了什麼？

Answer 1

問題出在SELECT *。由於可以在選擇中重複相同的列名稱。

明確提及列名稱。以下查詢將起作用。

SELECT YY.ACCOUNT_ID, YY.TRANSACTION_EVENT_ID 
FROM ( SELECT FT.ACCOUNT_ID, FT.TRANSACTION_EVENT_ID 
     FROM dbo.[TRANSACTION] TE 
     JOIN dbo.FUND_TRANSACTION FT ON TE.TRANSACTION_EVENT_ID = FT.TRANSACTION_EVENT_ID 
     JOIN ACCOUNT A ON FT.ACCOUNT_ID = A.ACCOUNT_ID 
    ) AS YY 

Answer 2

您必須指定要從哪個表TRANSACTION_EVENT_ID中選擇。您必須使用別名/表名指定列列表，而不是*。例如：

SELECT 
    YY.ACCOUNT_ID, 
    YY.TRANSACTION_EVENT_ID 
FROM 
    (SELECT A.ACCOUNT_ID, 
      TE.TRANSACTION_EVENT_ID 
    FROM dbo.TRANSACTION TE 
    JOIN dbo.FUND_TRANSACTION FT 
    ON TE.TRANSACTION_EVENT_ID = FT.TRANSACTION_EVENT_ID 
    JOIN ACCOUNT A 
    ON FT.ACCOUNT_ID = A.ACCOUNT_ID) AS YY