Example Here is an example of a function that uses a CURSOR FOR LOOP: CREATE OR REPLACE Function TotalIncome ( name_in IN varchar2 ) RETURN varchar2 IS total_val number(6); cursor c1 is SELECT monthly_income FROM employees WHERE name = name_in; BEGIN total_val := 0; FOR employee_...
Only use the cursor FOR loop when you want to perform an action for every record fetched. You should not exit prematurely from the loop using conditional logic.
END LOOP; RETURN total_val; END; In this example, we've created a cursor called c1. TheCURSOR FOR Loopwill terminate after all records have been fetched from the cursor c1. 译:在这个示例中,我们建立了一个名为c1的cursor。当所有c1中的记录都取后,CURSOR FOR Loop就会终止。 再分享一下我老...
1) PL/SQL cursor FOR LOOP example The following example declares an explicit cursor and uses it in the cursor FOR LOOP statement. DECLARE CURSOR c_product IS SELECT product_name, list_price FROM products ORDER BY list_price DESC; BEGIN FOR r_product IN c_product LOOP dbms_output.put_lin...
LOOP Statements… END LOOP; Example 1: Cursor For Loop With Simple Explicit Cursor SET SERVEROUTPUT ON; DECLARE CURSOR cur_RebellionRider IS SELECT first_name, last_name FROM employees WHERE employee_id >200; BEGIN FOR L_IDX IN cur_RebellionRider ...
1. When the user is asking for edits to their code, please output a simplified version of the code block that highlights the changes necessary and adds comments to indicate where unchanged code has been skipped. For example: ```language:path/to/file ...
In this example, an implicit cursor FOR LOOP statement prints the last name and job ID of every clerk whose manager has an ID greater than 120. BEGINFORitemIN(SELECTlast_name,job_idFROMemployeesWHEREjob_idLIKE'%CLERK%'ANDmanager_id>120ORDERBYlast_name)LOOPDBMS_OUTPUT.PUT_LINE('Name = '...
Oracle存储过程是一组为了完成特定功能的SQL语句集,它可以被存储在数据库中,并允许用户通过指定的名称和参数来重复调用。存储过程可以接受输入参数、返回输出参数,并可以执行包括数据查询、数据更新、数据删除等多种数据库操作。存储过程的主要作用是提高SQL代码的重用性、安全性和执行效率。 2. 在Oracle存储过程中如何使...
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; -- 打开游标 OPEN cur; -- 循环遍历结果集 read_loop: LOOP FETCH cur INTO example_data; IF done THEN LEAVE read_loop; END IF; -- 在这里处理每一行的数据 -- 例如,你可以打印数据或进行其他操作 SELECT example_data; END LOOP; -- 关...
CursorExample+process_data()+open_cursor()+fetch_data()+close_cursor() 5. 结尾 通过上述步骤,我们详细探讨了MySQL游标的性能管理及优化。希望新手能够通过理解和实践这些内容,提升对游标机制的掌握及性能优化的能力。使用游标时,要始终牢记性能问题,尽量减少资源消耗,从而提升整体数据库系统的效率。