Programmer Group

Preface Paging can be said to be a very common function. Most mainstream databases provide physical paging methods, such as Mysql's limit keyword, Oracle's ROWNUM keyword, etc.; as an ORM framework, Mybatis also provides paging functions. Next, the paging functions of Mybatis are introduced in detail. RowBounds page 1. Introduction to rowb ...

First of all, look at a business requirement: fuzzy query data by book name and paging function. Usually, you can write the query method as follows, but it is troublesome if there are many query dimensions. A new BaseDao is written to deal with this problem. The BaseDao code is as follows: package com.zking.eight.util; import j ...

a moment of fun Me: Hey, madam, there's Iced Black TeaMadame: YesMe: How much is a bottleEmpress: 3 piecesMe: Give me a bottle, give it, three piecesMadame: Come on, your iced black teaMe: Play, I want Iced Black tea. Do you want a cap for me?Mrs. Boss: This is another bottle. My family is sold out. Go to the next house and have a change. Q ...

In the technical forum, I saw a question like this: Now I have a table. There are 100 different words in it. Each word corresponds to about 20 phrases. I want to get 3 phrases randomly for each word through sql. How can I write it? I feel that the subject matter is very novel and the angle is very tricky. I haven't met similar needs in the in ...

1. For the installation of percona toolkit, please refer to: https://blog.csdn.net/yuanyk1222/article/details/100066788 2. Here are some uses of this tool: pt-online-schema-change The function can organize the table structure online, collect fragments, and add fields and indexes to large tables. Avoid blocking read and write operations by lo ...

Foreword: When you execute a SQL in MySQL, the statement is not completed within the time you expect. We usually log in to the MySQL database to see if something is wrong. One of the commands we usually use is show processlist to see which session s are there and what they are doing.When you see waiting for table metadata lock, you encounter an ...

Implement paging: there are two ways: traditional paging and classification based on pageHelper plug-in. The latter is recommended First, create a pageUtil tool manually to record all kinds of information of paging, and then use the tedious way to call data pageUtil class can be customized as required package com.imooc.project.util; /** ...

How to connect a mysql database with mysqli series functions? 1. PHP mysqli connect() function: mysqli connect() function opens a new connection to MySQL server. Syntax: mysqli connect (host (specify host name or IP address), username(mysql user name), password(mysql password), dbname (default database)) Open a new connection to the MySQL se ...

timestamp type partition, please move = > MySql table partition (based on time timestamp)Environmental Science:MySQL 8.0.18 (unverified for 5.6 and 5.7)The field type of partition condition is datetimeThe complete sql operation table partition statement is as follows: -- 1.Delete table drop table t_test; -- ============================== ...

Intro Recently, there is an idea that if you want to do something similar to ORM without writing sql statements, you can parse the expression tree, generate the sql statements to be executed, and finally execute the sql statements to return the corresponding results. Train of thought analysis The common sql statements basically have a certain m ...