http://dev.mysql.com/doc/refman/5.7/en/identifiers.html The following table describes the maximum length for each type of identifier. Identifier Maximum Length (characters) Database 64 (NDB storage engine: 63) Table 64 (NDB storage engine: 63) Column…

今天用sqlldr导入数据时候报错: " Record 1: Rejected - Error on table ks_test, column khname.Field in data file exceeds maximum length " 看到这个错误后以为是字段值过小导致,将原来的varchar2(1000) 改到了varchar2(2000) 发现还是不可以,依旧报如上错误,于是怀疑是sqlldr自身存在某些限制了. 查了下,发现果然如此. 原来表中定义的字段REFUSE_…

使用sqlldr导数时出现如下错误: " Record 1: Rejected - Error on table PC_PLANNAME, column PLANNAME.Field in data file exceeds maximum length " 上网查了一下找到原因了. 原来表中定义的字段 PLANNAME 虽然是VARCHAR(2000); 但是用控制文件(CTL)中默认为是char类型. 所以,当该列数据长度超过255(char类型长度)时会提示出错. 解决办法: 将…

Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays. Example 1: Input: A: [1,2,3,2,1] B: [3,2,1,4,7] Output: 3 Explanation: The repeated subarray with maximum length is [3, 2, 1]. Note: 1 <= len(A),…

Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays. Example 1: Input: A: [1,2,3,2,1] B: [3,2,1,4,7] Output: 3 Explanation: The repeated subarray with maximum length is [3, 2, 1].  Note: 1 <= len(A),…

MySQL Bugs: #34354: Feature request: EXPLAIN ALTER TABLE https://bugs.mysql.com/bug.php?id=34354 [SQL]EXPLAIN ALTER TABLE `answer` MODIFY COLUMN `content` text CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL COMMENT '修改字符集为utf8mb4,兼容表情符' AF…

Maximum Length of Repeated Subarray: Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays. Example 1: Input: A: [1,2,3,2,1] B: [3,2,1,4,7] Output: 3 Explanation: The repeated subarray with maximum len…

原题链接在这里:https://leetcode.com/problems/maximum-length-of-pair-chain/description/ 题目: You are given n pairs of numbers. In every pair, the first number is always smaller than the second number. Now, we define a pair (c, d) can follow another pair (a, b…

FireDAC 出现Variable length column[*] overflow. Value length - [80], column maximum length FireDAC的 TFDQuery组件访问SQLlite数据库,使用insert into语句插入一条数据长度为80的字符串,但是用 select * from 查询的时候却出现异常:[FireDac][DatS]-32. Variable length column[Namee] overflow. Value len…

Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays. Example 1: Input: A: [1,2,3,2,1] B: [3,2,1,4,7] Output: 3 Explanation: The repeated subarray with maximum length is [3, 2, 1]. Note: 1 <= len(A),…

lc 646 Maximum Length of Pair Chain 646 Maximum Length of Pair Chain You are given n pairs of numbers. In every pair, the first number is always smaller than the second number. Now, we define a pair (c, d) can follow another pair (a, b) if and only i…

Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays. Example 1: Input: A: [1,2,3,2,1] B: [3,2,1,4,7] Output: 3 Explanation: The repeated subarray with maximum length is [3, 2, 1]. Note: 1 <= len(A),…

原题链接在这里:https://leetcode.com/problems/maximum-length-of-a-concatenated-string-with-unique-characters/ 题目: Given an array of strings arr. String s is a concatenation of a sub-sequence of arr which have unique characters. Return the maximum possible le…

718. 最长重复子数组 718. Maximum Length of Repeated Subarray 题目描述 给定一个含有 n 个正整数的数组和一个正整数 s,找出该数组中满足其和 ≥ s 的长度最小的连续子数组.如果不存在符合条件的连续子数组,返回 0. LeetCode718. Maximum Length of Repeated Subarray 示例: 输入: s = 7, nums = [2,3,1,2,4,3] 输出: 2 解释: 子数组 [4,3] 是该条件下的长度最小的连…

Given two integer arrays A and B, return the maximum length of an subarray that appears in both arrays. Example 1: Input: A: [1,2,3,2,1] B: [3,2,1,4,7] Output: 3 Explanation: The repeated subarray with maximum length is [3, 2, 1]. Note: 1 <= len(A),…

You are given n pairs of numbers. In every pair, the first number is always smaller than the second number. Now, we define a pair (c, d) can follow another pair (a, b) if and only if b < c. Chain of pairs can be formed in this fashion. Given a set of…

题目如下: Given an array of strings arr. String s is a concatenation of a sub-sequence of arr which have unique characters. Return the maximum possible length of s. Example 1: Input: arr = ["un","iq","ue"] Output: 4 Explanation:…

714. Best Time to Buy and Sell Stock with Transaction Fee - Medium Your are given an array of integers prices, for which the i-th element is the price of a given stock on day i; and a non-negative integer fee representing a transaction fee. You may c…

检查报错日志提示:field in data file exceeds maximum length REMARK字段设置:varchar2(2000),报错的内容也没有超1000个字符 表中定义的字段 REMARK虽然是varchar2(2000),但控制文件(CTL)中默认为是char类型,所以,当该列数据长度超过255(char类型长度)时会提示出错 应该是sqlldr的限制,在ctl文件中配置 REMARK为:REMARK char(2000)…

[LeetCode]718. Maximum Length of Repeated Subarray 解题报告(Python) 标签(空格分隔): LeetCode 作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 题目地址:https://leetcode.com/problems/maximum-length-of-repeated-subarray/description/ 题目描述: Given two integer arr…

今天在看CU的时候,发现有人问有关optimize来表优化的问题,当年因为这个问题,困扰我很长一段时间,今天有空我把这个问题,用实际数据来展示出来,让大家可以亲眼来看看,optimize table的重要作用,而不是似是而非的估计了. 一,原始数据 1,数据量 mysql> select count(*) as total from ad_visit_history; +---------+ | total | +---------+ | 1187096 | //总共有118万多条数据 +-…

今天做数据迁移, 发现事务有时候可以回滚, 有时候不可以回滚, 最后一点点调试发现中间有段修改表结构的语句, 最终导致回滚失败. 1.MySQL最常用的两个表类型: InnoDB和MyISAM.MyISAM类型的表强调的是性能,其执行数度比InnoDB类型更快,但是不提供事务支持,而InnoDB提供事务支持.存储过程.视图.行级锁定等等高级数据库功能,若回滚失败,先检查表类型. SHOW ENGINES 语句可以查看当前的数据库支持的存储类 SHOW CREATE TABLE 表名;可以查看表的…

今天在看CU的时候,发现有人问有关optimize来表优化的问题,当年因为这个问题,困扰我很长一段时间,今天有空我把这个问题,用实际数据来展示出来,让大家可以亲眼来看看,optimize table的重要作用,而不是似是而非的估计了. 一,原始数据 1,数据量 mysql> select count(*) as total from ad_visit_history; +---------+ | total   | +---------+ | 1187096 |               …

来看看手册中关于 OPTIMIZE 的描述: OPTIMIZE [LOCAL | NO_WRITE_TO_BINLOG] TABLE tbl_name [, tbl_name] ... 如果您已经删除了表的一大部分,或者如果您已经对含有可变长度行的表(含有VARCHAR, BLOB或TEXT列的表)进行了很多更改,则应使用OPTIMIZE TABLE.被删除的记录被保持在链接清单中,后续的INSERT操作会重新使用旧的记录位置.您可以使用OPTIMIZE TABLE来重新利用未使用的空间,并整理…

service mysqld start 报错 090517 13:34:15 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 090517 13:34:15 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist 090517 13:34:15 mysq…

一个表的数据量有1000W条,那么查看这么表占据的硬盘空间时会发现,数据本身是300M,索引是200M 这个时候,删除掉500W条数据,这个时候数据本身150M,而索引还是200M左右 你删除数据时,mysql并不会回收,被已删除数据的占据的存储空间,以及索引位. 而是空在那里,而是等待新的数据来弥补这个空缺,这样就有一个缺少,如果一时半会,没有数据来填补这个空缺,那这样就太浪费资源了. 所以对于写比较频烦的表,要定期进行optimize,一个月一次,看实际情况而定了. optimize tab…

https://stackoverflow.com/questions/417142/what-is-the-maximum-length-of-a-url-in-different-browsers Short answer - de facto limit of 2000 characters If you keep URLs under 2000 characters, they'll work in virtually any combination of client and serv…

optimize table table_name 这个可以清除你表里面的空记录,每次清除的时候记得锁表 lock tables table_name  write|read; unlock tables;…

You are given n pairs of numbers. In every pair, the first number is always smaller than the second number. Now, we define a pair (c, d) can follow another pair (a, b) if and only if b < c. Chain of pairs can be formed in this fashion. Given a set of…

You are given n pairs of numbers. In every pair, the first number is always smaller than the second number. Now, we define a pair (c, d) can follow another pair (a, b) if and only if b < c. Chain of pairs can be formed in this fashion. Given a set of…