Question

我试图在MySQL中编写一个存储过程，根据指定的前缀删除和重命名表（在这种情况下，＆＃39; migrate _＆＃39;）。代码应递归重命名所有以＆＃39; migrate _＆＃39;开头的表。但是，在尝试运行它时，我没有留下任何错误。

BEGIN

SELECT COUNT(*) INTO @num_migrate
FROM information_schema.tables a 
WHERE a.table_name LIKE 'migrate_%';

IF (@num_migrate > 0) THEN
    SELECT concat( 'USE `md_rails`; DROP TABLE IF EXISTS `', 
            Replace(tbls.table_name,'migrate_',''), '`; ', 
        'RENAME TABLE `', tbls.table_name, '` TO `', 
            Replace(tbls.table_name,'migrate_',''), '`;' ) INTO @b
    FROM information_schema.tables tbls
    WHERE tbls.table_name LIKE 'migrate_%' LIMIT 1;
    PREPARE stmt FROM @b;
    EXECUTE stmt;
    CALL handle_migrated_tables();
END IF;


END

我得到的错误是：

Error Code: 1064. You have an error in your SQL syntax; check the manual
that corresponds to your MySQL server version for the right syntax to use 
near 'DROP TABLE IF EXISTS second_test; RENAME TABLE migrate_second_test TO 
second_tes' at line 1

我已经尝试自行运行select语句生成的代码，它可以满足我的需求，但由于某种原因，它在预备语句中并不喜欢它。

非常感谢任何帮助！

Answer 1

Lashane说对了！如果有人想知道，这是最终（工作）代码：

CREATE PROCEDURE `handle_migrated_tables`()
    BEGIN
        SET max_sp_recursion_depth=50;

        SELECT COUNT(*) INTO @num_migrate
        FROM information_schema.tables a 
        WHERE a.table_name LIKE 'migrate_%';

        IF (@num_migrate > 0) THEN

            SELECT tbls.table_name INTO @tbl
            FROM information_schema.tables tbls
            WHERE tbls.table_name LIKE 'migrate_%' LIMIT 1;

            SET @a = concat('DROP TABLE IF EXISTS md_rails.', Replace(@tbl, 'migrate_', ''));
            PREPARE stmt FROM @a;
            EXECUTE stmt;
            DEALLOCATE PREPARE stmt;

            SET @b = concat('RENAME TABLE md_rails.', @tbl, ' TO ', Replace(@tbl, 'migrate_', ''));
            PREPARE stmt FROM @b;
            EXECUTE stmt;
            DEALLOCATE PREPARE stmt;        

            CALL handle_migrated_tables();
        END IF;


    END

重命名表准备声明

1 个答案: