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...
FOR employee_rec in c1 LOOP total_val := total_val + employee_rec.monthly_income; 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...
With the cursor FOR loop, you do not have to explicitly: Declare a record into which the cursor’s row is fetched. Open the cursor. Fetch from the cursor into the record. Detect last record fetched in cursor. Close the cursor. All these steps are performed automatically by PL/SQL which ...
This Oracle tutorial explains how to use the CURSOR FOR LOOP in Oracle with syntax and examples. The syntax for the CURSOR FOR Loop in Oracle / PLSQL is:
游标(Cursor)是PL/SQL中处理查询结果集的重要工具。它提供了一种逐行处理查询结果的方法,使得我们可以在结果集上进行逐行操作,例如逐行更新、删除等。然而,游标在处理大数据量时可能会变得低效,因此,了解其使用方法和最佳实践对于提高程序性能至关重要。 一、游标的概念 游标可以看作是一个指针,它指向查询结果集中的...
PLSQL中对cursor 使用的小例子 plsql 开始 SETSERVEROUTPUTON;DECLAREv_empno emp.empno%TYPE; v_ename emp.ename%TYPE;CURSORemp_cursorISSELECTempno,enamefromempwhereempno<>1000;BEGINLOOPIFNOTemp_cursor%ISOPENTHENOPENemp_cursor;ENDIF;FETCHemp_cursorINTOv_empno,v_ename;EXITWHENemp_cursor%NOTFOUND;...
PLSQL中对cursor 使用的小例子 开始 SETSERVEROUTPUTON;DECLAREv_empno emp.empno%TYPE; v_ename emp.ename%TYPE;CURSORemp_cursorISSELECTempno,enamefromempwhereempno<>1000;BEGINLOOPIFNOTemp_cursor%ISOPENTHENOPENemp_cursor;ENDIF;FETCHemp_cursorINTOv_empno,v_ename;EXITWHENemp_cursor%NOTFOUND;...
cursor cur_users is select * from ma_users ; --声明了一个游标,可以打开游标OPEN cur_users ; --从游标中提取数据fetch cur_users into user_rec; --最后关闭游标close cur_users; --术语--静态SQL:当一个SQL语句所在的代码块被编译时,这个语句就完全指定的或者是固定的。--动态SQL:如果一个SQL语句...
PL/SQL cursor example We will use theordersandorder_itemstables from thesample databasefor the demonstration. The following statementcreates a viewthat returns the sales revenues by customers: CREATEVIEWsalesASSELECTcustomer_id, SUM(unit_price * quantity) total, ROUND(SUM(unit_price * quantity) ...
update departmentssetdepartment_name=department_name;dbms_output.put_line('update '||sql%rowcount||' records');end; CURSOR FOR IN LOOP隐式游标 代码语言:javascript 代码运行次数:0 运行 AI代码解释 //例子1:无参数,使用循环,无须打开关闭游标create or replace procedureTESTis ...