MYSQL存储过程：判断索引不存在时添加,入参和日志返回

存储过程：判断索引不存在时添加，支持入参和日志返回
调用方法：

CALL add_normal_index_if_not_exists('要添加索引的表','要添加索引的字段',@log);
select @log as '增加索引执行结果';

执行 效果
成功：

失败：

存储过程：

-- 存储过程：判断索引不存在时添加
DROP PROCEDURE IF EXISTS add_normal_index_if_not_exists;
DELIMITER $
CREATE PROCEDURE add_normal_index_if_not_exists(
    In target_table_name VARCHAR(100),
    In target_column_name varchar(100),
    OUT log varchar(100)
)
BEGIN
    DECLARE  target_database VARCHAR(100);
    SELECT DATABASE() INTO target_database;
    IF NOT EXISTS (
    SELECT * FROM information_schema.statistics
    WHERE lower(table_schema) = lower(target_database)
    AND lower(table_name) = lower(target_table_name)
    AND lower(COLUMN_NAME) = lower(target_column_name)
        )
    THEN
    set log = concat('create index idx_',target_column_name,' on ',target_table_name,'(',target_column_name,')' );
    set @statement = log;
    PREPARE STMT FROM @statement;
    EXECUTE STMT;
    else
    set log = concat(target_database,'.',target_table_name,'已存在字段',target_column_name,'的索引，不再添加');
END IF;
END;
$
DELIMITER ;

参考链接：
https://blog.youkuaiyun.com/TurboAnho/article/details/119808724