mysql sp 练习游标和预编译

create procedure Jack_count_cur_dual()
BEGIN
DECLARE tb_name VARCHAR(50);
DECLARE done int DEFAULT 0;
DECLARE mycur CURSOR for SELECT table_name FROM tt_countrows;
DECLARE CONTINUE HANDLER FOR NOT FOUND set done = 1;

DROP TABLE IF EXISTS tt_countrows;#删除，创建临时表
CREATE TEMPORARY TABLE tt_countrows(
table_name varchar(50),
table_count int
);

INSERT into tt_countrows(table_name)#向临时表中插入表名数据
select ‘autidor‘
UNION
SELECT ‘spprogram.books‘
UNION
SELECT ‘information_schema.files‘;
;

OPEN mycur;
myloop:LOOP
FETCH mycur into tb_name;#使用游标读取数据赋值给tb_name，得到表名

if done = 1 THEN 
leave myLoop; 
end if;

set @v_sql = CONCAT(‘select count(*) into @v_count from ‘,tb_name);#预编译查询表中数据数量的语句
PREPARE stmt FROM @v_sql;
EXECUTE stmt;

UPDATE tt_countrows SET table_count = @v_count #修改临时表中table_count字段，值为预编译语句中的count值
WHERE table_name = tb_name;

DEALLOCATE PREPARE stmt;
END LOOP myloop;
CLOSE mycur;
SELECT * FROM tt_countrows;#输出临时表结果并删除临时表
DROP TABLE tt_countrows;
END