內部查詢中的外部查詢的組函數

Question

我正在使用Oracle。我試圖編寫這樣的事情：

SELECT trans_type, 
(SELECT parameter_value FROM transaction_details WHERE id = MAX(t.trans_id)) 
FROM 
(SELECT trans_id, trans_type FROM transactions) t 
GROUP BY trans_type 

所以，我試圖在內部查詢中使用分組結果。但我得到的是我不能使用內部查詢內部一組函數的錯誤：

ORA-00934: group function is not allowed here 

你能比訴諸另一個外部查詢提供了一個替代其他？

UPDATE

按照要求，我張貼的實際查詢的一個較短的版本：

SELECT service_code, 
     currency, 
     (SELECT value FROM exchange_rate WHERE date_added = MIN(t.trans_date)) AS exchange_rate, 
     TRIM(TO_CHAR(SUM(amount), '9999999990.99')) AS amount, 
     TRIM(TO_CHAR(SUM(tax_amount), '9999999990.99')) AS tax_amount, 
     TRIM(TO_CHAR(SUM(total_amount), '9999999990.99')) AS total_amount 
    FROM (SELECT t.amount AS amount, 
       t.trans_date AS trans_date 
       t.tax_amount AS tax_amount, 
       t.total_amount AS total_amount, 
       td1.string_value AS service_code, 
       td2.string_value AS currency 
      FROM transac) t 
GROUP BY service_code, currency 

Answer 1

我想什麼你正在尋找是這樣的：

SELECT service_code, 
     currency, 
     er.value as exchange_rate, 
     TRIM(TO_CHAR(SUM(amount), '9999999990.99')) AS amount, 
     TRIM(TO_CHAR(SUM(tax_amount), '9999999990.99')) AS tax_amount, 
     TRIM(TO_CHAR(SUM(total_amount), '9999999990.99')) AS total_amount 
    FROM (SELECT t.amount AS amount, 
       t.tax_amount AS tax_amount, 
       t.total_amount AS total_amount, 
       td1.string_value AS service_code, 
       td2.string_value AS currency, 
       min(t.trans_date) 
        over (partition by td1.string, 
             td2.string) as min_trans_date 
      FROM transac t, table2 td1, table3 td2) t, 
      exchange_rate er 
    WHERE er.date_added = t.min_trans_date 

我不確定這是否是您的解決方案，因爲根據您的查詢，我無法確定您希望最小交易日期基於哪個組。此版本假定您想要給定服務代碼和貨幣組合的最早交易日期。

您正在運行到幾個問題，你的方法：

1. 需要或者是在GROUP BY子句 或受聚合 功能SELECT子句中的任何列。你有幾個列 不符合這個標準。

2. 您正嘗試使用 標量子查詢中的外部查詢中的聚合 函數。你不能這樣做 。充其量，您可以在嵌套查詢中獲得 聚合，然後在 之後引用該值。

Answer 2

這有什麼錯一個更傳統的查詢：

SELECT t.trans_type, td.parameter_value, MAX(t.trans_id) 
    FROM transactions t 
INNER 
    JOIN transaction_details td ON td.id = t.trans_id 
GROUP BY t.trans_type, td.parameter_value