TERADATA SQL：通過存儲在另一個表中的查詢結果填充一個表

Question

TERADATA SQL，我將SQL語句存儲在一個表中。我想用這些SQL語句的結果填充另一個表。每條行和每列的SQL語句都不相同。你能告訴我如何實現它嗎？我試圖通過存儲過程和Shell腳本獲得結果。但是，我無法正確編碼。

Answer 1

這裏有一個漂亮的準系統程序，用於解決這個問題。

1. 我們使用遊標來遍歷保存SQL語句
2. 我們採用第二光標同時通過第一遊標循環動態執行的SQL字符串您的源表：因爲它變得有點毛毛並將該SQL查詢的結果FETCH到一個變量中。

我會懷疑你會遇到各種各樣的錯誤，而得到這個設置，但我相信這是相當接近的工作過程：

CREATE PROCEDURE <yourdatbase>.MyNewProcedure() 
BEGIN 
    --Declare variables to hold the three fields as we loop through them with the cursor 
    --You'll need to change these types to match your table's data type so we can fetch 
    -- them without error inside the cursor loop 
    DECLARE customerID INT; 
    DECLARE customerName VARCHAR(50); 
    DECLARE sqlQUERY as VARCHAR(10000); 
    DECLARE source_table_cursor CURSOR FOR SELECT customerID, customerName, SQLQuery FROM <yourdatabase>.yoursourcetable FOR READ ONLY; 

    OPEN source_table_cursor; 
     looplabel: 
     LOOP 
      --We'll need a cursor for a dynamic statement 
      --And we'll also need an integer to catch your query 
      --results (Assuming they are all like (Sum(<somefield>) or some 
      --type of INT 
      DECLARE C1 CURSOR FOR S1; 
      DECLARE sqlResults as INT; 

      FETCH source_table_cursor INTO customerID, customerName, sqlQuery; 

      --WOAH THERE! Cursor issues something went wrong die die die 
      IF (SQLSTATE ='02000') THEN 
       LEAVE label1; 
      END IF;  

      --Now that we have a record and a sql statement we will need another cursor 
      --where we will execute, dynamically, the SQL statement and then fetch the 
      --single record result to update our target table   
      PREPARE S1 FROM sqlQuery; 
      OPEN C1; 
       FETCH C1 INTO sqlResults; 

       --Now we can INsert into your target table 
       INSERT INTO <yourdatabase>.yourtargettable (customerID, customerName SQL_RESULT) 
        VALUES (customerID, customerName, sqlResults); 

      CLOSE C1; 

     END LOOP looplabel; 
    CLOSE demographic_cursor; 
END