Question

TERADATA SQL，我将SQL语句存储在表中。我想用另一个表填充那些SQL语句的结果。每个行和每列的SQL语句都不同。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

这是一个很好的准系统程序，用于拉出这样的东西。它变得有点毛茸茸，因为：

我们正在使用游标来遍历包含SQL语句的源表
我们在循环第一个游标时使用第二个游标来动态执行SQL String并将该SQL查询的结果FETCH转换为变量。

我怀疑你在设置这个问题时会遇到各种各样的错误，但我相信这非常接近于一个工作程序：

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

TERADATA SQL：通过存储在另一个表中的查询结果填充一个表

1 个答案: