How to export multiple query results in PL/SQL?

In PL/SQL, you can use a cursor to fetch multiple query results. The specific steps are as follows:

1. Declare a cursor variable and specify the query statement.

DECLARE
    CURSOR c1 IS SELECT * FROM table1;
    CURSOR c2 IS SELECT * FROM table2;
    ...

1. Declare a variable to store the query results.

    -- 声明变量来存储表1的查询结果
    v_col1 table1.column1%TYPE;
    v_col2 table1.column2%TYPE;
    ...
    
    -- 声明变量来存储表2的查询结果
    v_col3 table2.column1%TYPE;
    v_col4 table2.column2%TYPE;
    ...

1. Open the cursor.

    OPEN c1;
    OPEN c2;
    ...

1. Traverse the cursor using loop statements and assign the query results to the corresponding variables.

    LOOP
        -- 将表1的查询结果赋值给变量
        FETCH c1 INTO v_col1, v_col2;
        EXIT WHEN c1%NOTFOUND;
        
        -- 对查询结果进行处理
        ...
        
        -- 将表2的查询结果赋值给变量
        FETCH c2 INTO v_col3, v_col4;
        EXIT WHEN c2%NOTFOUND;
        
        -- 对查询结果进行处理
        ...
    END LOOP;

1. Close the cursor.

    CLOSE c1;
    CLOSE c2;
    ...

By following the above steps, multiple query results can be exports and processed accordingly.