Mysql 存储过程查询结果赋值到变量的方法

drop table if exists test_tbl;
create table test_tbl (name varchar(20), status int(2));
insert into test_tbl values('abc', 1),('edf', 2),('xyz', 3);

drop procedure IF EXISTS pro_test_3;
delimiter //
create procedure pro_test_3()
begin
--  方式 1
DECLARE cnt INT DEFAULT 0;
select count(*) into cnt from test_tbl;
select cnt;

--  方式 2
set @cnt = (select count(*) from test_tbl);
select @cnt;

--  方式 3
select count(*) into @cnt1 from test_tbl;
select @cnt1;

--  多个列的情况下似乎只能用 into 方式
select max(status), avg(status) into @max, @avg from test_tbl;
select @max, @avg;
end
//
delimiter ;

call pro_test_3();