PL/SQL 11g R2 —— 定义PL/SQL变量 ！

identifier [constant] datatype [not null] [:= | default expr];v_ename varchar2(10);v_sal number(6,2);v_tax constant number(3,2) := 5.5;v_data data;v_b boolean not null default false; 

例子1：

SQL> set serveroutput onSQL> declare  2    v_myname varchar2(20);  3  begin  4    dbms_output.put_line('My name is :' || v_myname);  5    v_myname := 'zhangshenghong';  6    dbms_output.put_line('My name is :' || v_myname);  7  end;  8  /My name is :My name is :zhangshenghongPL/SQL 过程已成功完成。

例子2：

SQL> set serveroutput onSQL> declare  2    v_myname varchar2(20) default 'zhangqu';  3  begin  4    v_myname := 'zhangshenghong';  5    dbms_output.put_line('My name is :' || v_myname);  6  end;  7  /My name is :zhangshenghongPL/SQL 过程已成功完成。

例子3：

SQL> set serveroutput onSQL> declare  2    v_event varchar2(20) := 'Wather''s day';  3  begin  4    dbms_output.put_line(v_event);  5    v_event := q'!Father's day!';  6    dbms_output.put_line(v_event);  7    v_event := q'[Monther's day]';  8    dbms_output.put_line(v_event);  9  end; 10  /Wather's dayFather's dayMonther's dayPL/SQL 过程已成功完成。

绑定变量用法：

SQL> set serveroutput onSQL> variable b_salary number;SQL> begin  2    select salary into :b_salary from employees where employee_id = 178;  3  end;  4  /PL/SQL 过程已成功完成。SQL> print b_salary;  B_SALARY----------      7000SQL> select first_name,last_name from employees where salary = :b_salary;FIRST_NAME           LAST_NAME-------------------- -------------------------Oliver               TuvaultSarath               SewallKimberely            Grant