mysql存储过程写法—动态参数运用

 --删除

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drop procedure if exists up_common_select

  --创建

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CREATE PROCEDURE `up_common_select`
  (
   in t_name varchar(50)
  )
  begin
   declare v_sql varchar(500);
   set v_sql= concat('select * from ',t_name);
   select v_sql;
--注意:prepare(预处理)execute stmt using @var,只能跟@var变量,declare和传入的变量不行!!!
   set @v_sql=v_sql;
   prepare stmt from @v_sql;
   EXECUTE stmt ;
   deallocate prepare stmt;
  end;

  --调用

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call up_common_select('admin_authority');

  注意事项

  1 mysql5.0.13之后支持在存储过程中调用prepare

  2 prepare stmt from 'select * from ?'; (错)

  mysql5.0.24,prepare尚不支持 表名做变量!

  解决方案:用 contat()函数,组合字符串

  3 execute stmt [using @var,@var2]

  必须是@var形式的变量,传入的参数变量,declare变量不行

  4. deallocate prepare stmt; 显式的释放prepare,如果不释放,mysql会释放,!

原文地址:https://www.cnblogs.com/jiligalaer/p/3962328.html