MySQL存储过程-把一个查询的结果，做为变量，更新另一张表

create table t1(c1 varchar(20));
insert into t1 select 't1';

create table t2(c2 varchar(20));
insert into t2 select 't2';

delimiter $$
DROP PROCEDURE IF EXISTS test_1 ;
CREATE PROCEDURE test_1()
begin
DECLARE a varchar(20);
select c1 INTO a from t1;
update t2 set c2=a;
end;
$$
DELIMITER ;

call test_1();