oracle儲存過程中如何執行動態SQL語句
有時需要在oracle儲存過程中執行動態SQL語句 ,例如表名是動態的,或欄位是動態的,或查詢命令是動態的,可用下面的方法:
set serveroutput on
declare
n number;
sql_stmt varchar2(50);
t varchar2(20);
begin
execute immediate 'alter session set nls_date_format=''YYYYMMDD''';
t := 't_' || sysdate;
sql_stmt := 'select count(*) from ' || t;
execute immediate sql_stmt into n;
dbms_output.put_line('The number of rows of ' || t || ' is ' || n);
end;
如果動態SQL語句 很長很複雜,則可用包裝.
CREATE OR REPLACE PACKAGE test_pkg
IS
TYPE cur_typ IS REF CURSOR;
PROCEDURE test_proc (v_table VARCHAR2,t_cur OUT cur_typ);
END;
/
CREATE OR REPLACE PACKAGE BODY test_pkg
IS
PROCEDURE test_proc (v_table VARCHAR2,t_cur OUT cur_typ)
IS
sqlstr VARCHAR2(2000);
BEGIN
sqlstr := 'SELECT * FROM '||v_table;
OPEN t_cur FOR sqlstr;
END;
END;
/
在oracle中批量匯入,匯出和刪除表名以某些字元開頭的表
spool c:/a.sql
select 'drop table ' || tname || ';' from tab where tname like 'T%';
spool off
@c:/a