mysql - 随笔分类(第12页) - papering

Why Stored Procedures?

摘要：http://www.w3resource.com/mysql/mysql-procedure.php Stored procedures are fast. MySQL server takes some advantage of caching, just as prepared stateme 阅读全文

posted @ 2016-12-27 10:19 papering 阅读(148) 评论(0) 推荐(0)

delimiter

摘要：http://www.mysqltutorial.org/getting-started-with-mysql-stored-procedures.aspx The first command is DELIMITER // , which is not related to the stored 阅读全文

posted @ 2016-12-27 09:59 papering 阅读(196) 评论(0) 推荐(0)

Memory Allocation in the MySQL Server

摘要：https://dev.mysql.com/doc/internals/en/memory-allocation-mysql-server.html MySQL Internals Manual / Memory Allocation / Memory Allocation in the MySQL 阅读全文

posted @ 2016-12-23 20:02 papering 阅读(251) 评论(0) 推荐(0)

corresponding SQLSTATE values general error

摘要：http://dev.mysql.com/doc/refman/5.7/en/error-messages-server.html B.3 Server Error Codes and Messages MySQL programs have access to several types of e 阅读全文

posted @ 2016-12-23 16:01 papering 阅读(284) 评论(0) 推荐(0)

控制变量法-初中物理-Nobel Lecture, December 12, 1929-php执行SET GLOBAL connect_timeout=2效果

摘要：Navicat 'ww' root账户用php、Navicat、\MySQL\bin\mysql.exe 执行阅读全文

posted @ 2016-12-23 15:41 papering 阅读(397) 评论(0) 推荐(0)

IN()

摘要：High Performance My SQL, Third Edition Consider the followingWHERE clause: WHERE eye_color IN('brown','blue','hazel') AND hair_color IN('black','red', 阅读全文

posted @ 2016-12-23 12:14 papering 阅读(246) 评论(0) 推荐(0)

max_allowed_packet

摘要：http://dev.mysql.com/doc/refman/5.7/en/comparison-operators.html#function_in The number of values in the IN list is only limited by the max_allowed_pa 阅读全文

posted @ 2016-12-23 12:10 papering 阅读(155) 评论(0) 推荐(0)

LENGTH() CHAR_LENGTH()

摘要：http://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_length LENGTH(str) Returns the length of the string str, measured in bytes. A mu 阅读全文

posted @ 2016-12-23 12:06 papering 阅读(172) 评论(0) 推荐(0)

How MySQL Uses Indexes CREATE INDEX SELECT COUNT(*)

摘要：MySQL :: MySQL 5.7 Reference Manual :: 9.3.1 How MySQL Uses Indexeshttps://dev.mysql.com/doc/refman/5.7/en/mysql-indexes.html CREATE INDEX SELECT COUN 阅读全文

posted @ 2016-12-20 17:14 papering 阅读(229) 评论(0) 推荐(0)

but this usually doesn’t gain you anything.

摘要：The following rules describe the possibilities for defining the first TIMESTAMP column in a table with the current timestamp for both the default and 阅读全文

posted @ 2016-12-20 11:21 papering 阅读(242) 评论(0) 推荐(0)

SET GLOBAL slow_query_log=1

摘要：[SQL]SET slow_query_log=1 [Err] 1229 - Variable 'slow_query_log' is a GLOBAL variable and should be set with SET GLOBAL SHOW VARIABLES LIKE '%slow%' SET GLOBAL slow_query_log=1 SHOW VARIABLES ... 阅读全文

posted @ 2016-12-20 10:54 papering 阅读(331) 评论(0) 推荐(0)

SET GLOBAL long_query_time=0

摘要：1 SHOW VARIABLES LIKE '%long%' 2 SET GLOBAL long_query_time=0 阅读全文

posted @ 2016-12-20 10:44 papering 阅读(264) 评论(0) 推荐(0)

mysql 索引聚簇索引聚集索引非聚集索引 clustered indexes nonclustered InnoDB 索引组织表 Index Organizied Table 堆组织表Heap Organizied Table

摘要：聚集索引和非聚集索引在索引结构中都只包含键和记录标识符。记录标识符总是指向数据页中的行。使用聚集索引，数据库管理器将尝试以与索引页中相应键相同的顺序保持数据页中的数据。因此，数据库管理器尝试将具有相似键的行插入到相同的页面上。如果对表进行了重组，则按照索引键的顺序将数据插入数据页。与非聚集索引的阅读全文

posted @ 2016-12-20 10:30 papering 阅读(268) 评论(0) 推荐(0)

mysqli_query($link,'SET group_concat_max_len=8192');

摘要：1 mysqli_query($link,'SET group_concat_max_len=8192'); 2 $sql = 'SELECT GROUP_CONCAT(w) FROM ---'; 3 mysqli_query($link,$sql); 阅读全文

posted @ 2016-12-17 11:14 papering 阅读(232) 评论(0) 推荐(0)

Bit-Value Type

摘要：https://dev.mysql.com/doc/refman/5.7/en/bit-type.html MySQL 5.7 Reference Manual / ... / Bit-Value Type - BIT 12.2.4 Bit-Value Type - BIT The BIT data 阅读全文

posted @ 2016-12-15 16:32 papering 阅读(216) 评论(0) 推荐(0)

a compromise between lock overhead and data safety

摘要：High Performance My SQL THIRD EDITION A locking strategy is a compromise between lock overhead and data safety, and thatcompromise affects performance 阅读全文

posted @ 2016-12-13 16:28 papering 阅读(144) 评论(0) 推荐(0)

Connection Management and Security

摘要：High Performance My SQL THIRD EDITION Each client connection gets its own thread within the server process. The connection’squeries execute within tha 阅读全文

posted @ 2016-12-13 16:26 papering 阅读(149) 评论(0) 推荐(0)

21335592 ROWS

摘要：CREATE TABLE w_big SELECT * FROM ( SEELCT * FROM w_tab UNION ALL SELECT * FROM w_tab_copy_modify ) AS w_tmp 阅读全文

posted @ 2016-12-02 20:13 papering 阅读(139) 评论(0) 推荐(0)

wdate-year-month-week-gategory-amount-coin

摘要：2016-12-02 19:46:39 the whole table DISTINCT field SUM(field) COUNT(field) 888983 rows OK 阅读全文

posted @ 2016-11-30 19:48 papering 阅读(180) 评论(0) 推荐(0)

从一个表复制信息到另一个表

摘要：SQL INSERT INTO SELECT 语句 | 菜鸟教程 https://www.runoob.com/sql/sql-insert-into-select.html 我们可以从一个表中复制所有的列插入到另一个已存在的表中： INSERT INTO table2SELECT * FROM t 阅读全文

posted @ 2016-11-30 12:32 papering 阅读(227) 评论(0) 推荐(0)

papering

随笔分类 - mysql