10

我想从包含first_name列的每个表中输出数据。我将以下过程放在一起，但在我的循环中，mysql 按字面意思解释表名，而不是评估变量table_name。解决方法是什么？

delimiter //

drop procedure if exists hunt //
create procedure hunt()
begin
    DECLARE done int default false;
    DECLARE table_name CHAR(255);

    DECLARE cur1 cursor for SELECT TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS 
        WHERE TABLE_SCHEMA = "wholesale_production" and COLUMN_NAME LIKE "%first%" ;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
    open cur1;

    myloop: loop
        fetch cur1 into table_name;
        if done then
            leave myloop;
        end if;
        select * from `wholesale_production`.table_name where created_at >= '2012-10-01';
    end loop;

    close cur1;
end //

delimiter ;

call hunt();
4

4 回答 4

16

试试这个：

delimiter //

drop procedure if exists hunt //
create procedure hunt()
begin
    DECLARE done BOOL default false;
    DECLARE tablename CHAR(255);

    DECLARE cur1 cursor for SELECT TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS 
        WHERE TABLE_SCHEMA = "wholesale_production" and COLUMN_NAME LIKE "%first%" ;
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
    open cur1;

    myloop: loop
        fetch cur1 into tablename;
        if done then
            leave myloop;
        end if;
        set @sql = CONCAT('select * from `wholesale_production`.', tablename, ' where created_at >= ''2012-10-01''');
        prepare stmt from @sql;
        execute stmt;
        drop prepare stmt;
    end loop;

    close cur1;
end //

delimiter ;

call hunt();
于 2012-10-04T00:26:49.417 回答
1

对上面的内容进行一点编辑以迭代 ahtoug 所有表并选择它们。

delimiter //
drop procedure if exists hunt //
create procedure hunt()
begin
    DECLARE done int default false;
    DECLARE table_name CHAR(255);

    DECLARE cur1 cursor for SELECT TABLE_NAME FROM INFORMATION_SCHEMA.TABLES
                  WHERE table_schema ='mbu4u';
   DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;
    open cur1;
       myloop: loop
        fetch cur1 into table_name;
        if done then
            leave myloop;
        end if;
        set @sql = CONCAT('select * from `mbu4u`.',table_name);
        prepare stmt from @sql;
        execute stmt;
        drop prepare stmt;
    end loop;

    close cur1;
end //

delimiter //
于 2015-04-27T10:00:47.387 回答
0

table_name 是保留标记在“DECLARE table_name CHAR(255);”中使用另一个变量名

于 2017-04-26T10:35:37.213 回答
-3

在 cur1 你正在使用 TABLE_NAME 那里尝试使用表的真实名称

于 2012-10-04T00:16:25.113 回答