Oracle实现动态SQL的拼装要领(2)-木庄网络博客

简而言之，掌握这三点，就应该能拼装出能用的SQL。至于如果使用绑定变量输入输出，则需要使用into using关键字。

set serveroutput on; 
declare
incoming date:=sysdate-10;
outgoing int;
begin
execute immediate 'select COUNT(*) FROM user_objects where created > :incoming' into outgoing using incoming ;
dbms_output.put_line(' count is: ' || outgoing);
end;

使用using的好处，就是不用去转date类型为varchar类型，再转回去date类型这种繁琐的操作。

SQL代码如下：

declare
incoming date:=sysdate-10;
outgoing int;
begin
execute immediate 'insert into t_object(a) select COUNT(*) FROM user_objects where created > :incoming' into outgoing using incoming ;
dbms_output.put_line(' count is: ' || outgoing);
end;

ORA-01007: 变量不在选择列表中
ORA-06512: 在 line 6

tom这样解释这个错误：Followup November 24, 2004 - 7am Central time zone:
you have to use DBMS_SQL when the number of outputs is not known until run time.

Sql代码如下：

declare 
v_cursor number; --定义游标 
v_string varchar2(2999); 
v_row number; 
begin 
v_string := 'insert into t_object(a) select COUNT(*) FROM user_objects where created > :incoming';--操作语句,其中:name是语句运行时才确定值的变量 
v_cursor:=dbms_sql.open_cursor;--打开处理游标 
dbms_sql.parse(v_cursor,v_string,dbms_sql.native);--解释语句 
dbms_sql.bind_variable(v_cursor,':incoming',sysdate-30); --给变量赋值 
v_row := dbms_sql.execute(v_cursor);--执行语句 
dbms_sql.close_cursor(v_cursor);--关闭游标 
--dbms_output.put_line(v_row); 
commit; 
exception 
when others then 
dbms_sql.close_cursor(v_cursor); --关闭游标 
rollback; 
end;

标签：Oracle

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