MySQL 将 EXECUTE 的结果保存在变量中?

问题描述

如何将 EXECUTE 语句的结果保存到变量中?类似的东西

How do I save the results of EXECUTE statement to a variable? Something like

SET a = (EXECUTE stmtl);

推荐答案

如果你想用准备好的语句来做到这一点，那么你需要在原始语句声明中包含变量赋值.

If you want to do this with a prepared statement, then you need to include the variable assignment in the original statement declaration.

如果您想使用存储的例程，那就更容易了.可以将存储函数的返回值直接赋值给变量，存储过程支持输出参数.

If you want to use a stored routine it's easier. You can assign the return value of a stored function directly to a variable, and stored procedures support out parameters.

示例:

准备好的声明:

PREPARE square_stmt from 'select pow(?,2) into @outvar';
set @invar = 1;
execute square_stmt using @invar;
select @outvar;
+---------+
| @outvar |
+---------+
|       1 |
+---------+
DEALLOCATE PREPARE square_stmt;

存储函数:

delimiter $$
create function square_func(p_input int) returns int
begin
  return pow(p_input,2);
end $$
delimiter ;

set @outvar = square_func(2);
select @outvar;
+---------+
| @outvar |
+---------+
|       4 |
+---------+

存储过程:

delimiter $$
create procedure square_proc(p_input int, p_output int)
begin
  set p_output = pow(p_input,2);
end $$
delimiter ;

set @outvar = square_func(3);
call square_proc(2,@outvar);
select @outvar;
+---------+
| @outvar |
+---------+
|       9 |
+---------+

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