mysql存储过程赋值

-- 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;