TERADATA SQL：通过存储在另一个表中的查询结果填充一个表

Question

TERADATA SQL，我将SQL语句存储在一个表中。我想用这些SQL语句的结果填充另一个表。每条行和每列的SQL语句都不相同。你能告诉我如何实现它吗？我试图通过存储过程和Shell脚本获得结果。但是，我无法正确编码。

Answer 1

这里有一个漂亮的准系统程序，用于解决这个问题。

1. 我们使用游标来遍历保存SQL语句
2. 我们采用第二光标同时通过第一游标循环动态执行的SQL字符串您的源表：因为它变得有点毛毛并将该SQL查询的结果FETCH到一个变量中。

我会怀疑你会遇到各种各样的错误，而得到这个设置，但我相信这是相当接近的工作过程：

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