Tag:Original table

  • MSSQL · ideas of cleaning up large amount of historical data

    Time:2021-7-22

    Reading time |0.6 minutes word count |963.2 characters primary coverage |1. Introduction & background “MSSQL · ideas for cleaning up large amount of historical data“ Author | SCscHero Writing time | 2021/7/15 PM10:45 Article type |Series Completion |Completed motto Every great cause has a trivial beginning. 1、 Introduction & background    Completion: 100% a) Coping with […]

  • How to deal with the addition of fields in MySQL large tables without downtime

    Time:2021-5-7

    It’s always a headache to add fields to a table of tens of millions or even more in MySQL. How to deal with this situation? In this paper, three common scenarios are used to illustrate the case. 1. Environmental preparation Database version:   5.7.25-28 (percona branch) Server configuration:  Three CentOS 7 virtual machines with 2cpu […]

  • In mysql, a field of a table is updated to another table by associating update

    Time:2021-4-13

    Then I wrote an articlehttps://www.cnblogs.com/lingyejun/p/11915413.html What do you do Update book_ Borrow table to set the students in it_ Name is the name in the student table, and the association condition isbook_borrow.student_id = student_id Student table book_ Borrow table Several different update methods Keep the update of the original table data Only some data in […]

  • Two methods of adding summary row in PL / SQL exercise 6

    Time:2020-8-18

    Question: the name of the statistical department and the corresponding number of people,Add to last column summaryOriginal result, no summary column: SELECT D.DNAME,COUNT(*) FROM DEPT D LEFT JOIN EMP E ON D.DEPTNO = E.DEPTNO GROUP BY D.DNAME Method one principle: Union all of the two tables,One of the tables is the original table, and the […]

  • Technology sharing | sharing of usage scenarios of percona Toolkit

    Time:2020-7-20

    Author: Du Jinyang More convenient data archiving Pt Archiver Some timeliness data need to be filed and recycled after reaching certain conditions.The PT archiver tool can help us quickly archive and recycle data rows #Archive to other databases and delete the corresponding rows in the original table pt-archiver –source h=172.20.134.1,P=5722,u=repl,p=repl,D=sbtest,t=sbtest1,A=utf8 –where “id<=1000” –dest h=172.20.134.3,P=5722,u=dba,p=dba,D=sbtest,t=sbtest1,A=utf8 #Archive […]

  • Oracle (PLSQL) introduction 1

    Time:2020-6-5

    Oracle installation, user authorization, table operation, data type, DDL table, DML data. Next: Oracle introduction 2 Learning video: https://www.bilibili.com/video/BV1tJ411r7EC?p=15 Baidu cloud installation package is attached to the installation tutorial: https://blog.csdn.net/qq_ 40774525/article/details/79919057 Oracle Baidu cloud installation package: https://pan.baidu.com/s/1qVWwCUR37j2JxEecYbe5HQ Extraction code: 5abz After the Oracle service above is installed, open the client of SQL developer and the […]

  • Horizontal segmentation of MySQL tables

    Time:2020-2-29

    Background The boss arranged to divide a large capacity table into several tables according to the year. 2、 Horizontal division Horizontal splitting refers to the splitting of data table rows. When the number of rows in the table exceeds one million, it will slow down. At this time, the data in one table can be […]