如何在oracle中獲取數字作為別名

Question

我有以下查詢：

Select 
  Y1 as Cast(v_FY0 - 5 - v_offset as char) 
from 
  TBLTMPLTS_LOAD_INCSTATEMT_RAW;

其中 v_FY0 是 NUMBER(10) 和 v_OffSet Number(10)；

執行后，我得到： v_FY0 =2018 and v_OffSet = 0;

所以語句變成：

SELECT 
  Y1 as CAST(2018 - 5 - 0 AS CHAR) 
FROM 
  TBLTMPLTS_LOAD_INCSTATEMT_RAW;

基本上，我想要實現的是從表 TBLTMPLTS_LOAD_INCSTATEMT_RAW 中選擇列 Y1 時，列名應該是上面表達式中給出的 v_FY0 和 v_OffSet 的計算值，我不能直接寫它，因為它在循環中運行循環 v_FY0 和 v_OffSet 有不同的值，從而根據 v_FY0 和 v_OffSet 的值每次更改列名。

但我收到錯誤：

ORA -00923: FROM 關鍵字未在預期位置找到

如何解決這個問題？

編輯：正如 Kaushik Nayak 所說，我上面提供的代碼是下面顯示的 unpivot 語句的一部分。我只去掉了我認為導致問題的部分，讓每個人都清楚地理解。

v_SQL := '
-- ==========================================================
--  Main Unpivot Table -  To move years from column headings 
--  to rows values
-- ==========================================================

SELECT 
 CAST(FieldYear AS Number) FieldYear
, FieldType
, CASE FieldValue 
    WHEN '''' THEN NULL
    ELSE CAST (FieldValue AS Number(38,8))
  END FieldValue
FROM 
(SELECT ' || 
v_InsertType ||' AS FieldType
,Y1 as ' || CAST(v_FY0 - 5 - v_OffSet AS CHAR) || '
,Y2 as ' || CAST(v_FY0 - 4 - v_OffSet AS CHAR) || '
,Y3 as ' || CAST(v_FY0 - 3 - v_OffSet AS CHAR) || '
,Y4 as ' || CAST(v_FY0 - 2 - v_OffSet AS CHAR) || '
,Y5 as ' || CAST(v_FY0 - 1 - v_OffSet AS CHAR) || '
,Y6 as ' || CAST(v_FY0     - v_OffSet AS CHAR) || ' 
,Y7 as ' || CAST(v_FY0 + 1 - v_OffSet AS CHAR) || '
,Y8 as ' || CAST(v_FY0 + 2 - v_OffSet AS CHAR) || '
,Y9 as ' || CAST(v_FY0 + 3 - v_OffSet AS CHAR) || '
,Y10 as ' || CAST(v_FY0 + 4 - v_OffSet AS CHAR) || '
,Y11 as ' || CAST(v_FY0 + 5 - v_OffSet AS CHAR) || '
,Y12 as ' || CAST(v_FY0 + 6 - v_OffSet AS CHAR) || '
,Y13 as ' || CAST(v_FY0 + 7 - v_OffSet AS CHAR) || '
,Y14 as ' || CAST(v_FY0 + 8 - v_OffSet AS CHAR) || '
,Y15 as ' || CAST(v_FY0 + 9 - v_OffSet AS CHAR) || '
,Y16 as ' || CAST(v_FY0 + 10 - v_OffSet AS CHAR) || '
,Y17 as ' || CAST(v_FY0 + 11 - v_OffSet AS CHAR) || '
,Y18 as ' || CAST(v_FY0 + 12 - v_OffSet AS CHAR) || '
,Y19 as ' || CAST(v_FY0 + 13 - v_OffSet AS CHAR) || '
,Y20 as ' || CAST(v_FY0 + 14 - v_OffSet AS CHAR) || '
,Y21 as ' || CAST(v_FY0 + 15 - v_OffSet AS CHAR) || '
,Y22 as ' || CAST(v_FY0 + 16 - v_OffSet AS CHAR) || '
,Y23 as ' || CAST(v_FY0 + 17 - v_OffSet AS CHAR) || '
,Y24 as ' || CAST(v_FY0 + 18 - v_OffSet AS CHAR) || '
,Y25 as ' || CAST(v_FY0 + 19 - v_OffSet AS CHAR) || '
,Y26 as ' || CAST(v_FY0 + 20 - v_OffSet AS CHAR) || '
,Y27 as ' || CAST(v_FY0 + 21 - v_OffSet AS CHAR) || '
,Y28 as ' || CAST(v_FY0 + 22 - v_OffSet AS CHAR) || '
,Y29 as ' || CAST(v_FY0 + 23 - v_OffSet AS CHAR) || '
,Y30 as ' || CAST(v_FY0 + 24 - v_OffSet AS CHAR) || '
,Y31 as ' || CAST(v_FY0 + 25 - v_OffSet AS CHAR) || '
,Y32 as ' || CAST(v_FY0 + 26 - v_OffSet AS CHAR) || '
,Y33 as ' || CAST(v_FY0 + 27 - v_OffSet AS CHAR) || '
,Y34 as ' || CAST(v_FY0 + 28 - v_OffSet AS CHAR) || '
,Y35 as ' || CAST(v_FY0 + 29 - v_OffSet AS CHAR) || '

FROM ' || 
    v_tblInsertType || ') UP
UNPIVOT
(FieldValue FOR FieldYear IN 
(' || CAST(v_FY0 - 5 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 - 4 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 - 3 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 - 2 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 - 1 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0     - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 1 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 2 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 3 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 4 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 5 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 6 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 7 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 8 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 9 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 10 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 11 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 12 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 13 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 14 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 15 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 16 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 17 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 18 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 19 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 20 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 21 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 22 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 23 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 24 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 25 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 26 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 27 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 28 - v_OffSet AS CHAR) || '
,' || CAST(v_FY0 + 29 - v_OffSet AS CHAR) || '
)
)AS unpvt

Execute immediate v_SQL;

但是我收到錯誤 - ORA-00923: FROM Keyword not found where expected.

Answer 1

結果集中的列名是標識符。 必須在准備 SQL 語句時指定/知道標識符。 不可能在語句的執行中或在語句的執行中動態修改列名（列別名）。

滿足此類要求的規范方法是運行兩條SQL 語句。 第一條語句的結果可用於生成第二條 SQL 語句的文本。

---

編輯

在完整代碼中（在最近對問題的編輯中添加），似乎在為v_SQL的語句中缺少最后的結束單引號。

似乎我們希望EXECUTE IMMEDIATE是一個單獨的語句，而不是分配給v_SQL的值的一部分。

在最初的問題中，（對我而言）不清楚問題出在 PL/SQL 塊的上下文中，即v_offset是對 PL/SQL 變量而不是列的引用。

對於調試，請考慮在賦值后立即使用 DBMS_OUTPUT-ing v_SQL的值。