mysql update multiple columns

contains a value of 1, the following two statements have the same effect:[SQL]View PlainCopy Mysql>INSERT into table (a,b,c) VALUES -OnDUPLICATE KEY UPDATE c=c+1; mysql>UPDATE table SET c=c+1 WHERE a=1; If the row is inserted as a new record, the value of the affected row is 1, and if the o

Label: Multiple table Updates in MySQL 3.23, you can use LIMIT # to make sure that only a given number of record rows is changed. if an ORDER BY clause is used (supported from MySQL 4.0.0), the record row is updated in the specified order.This is actually only useful with LIMIT. starting with MySQL 4.0.4, you can a

same table by other processes. Only when the write lock is released, to read and write other processes. The following example is used to verify the above points. The data table gz_phone contains more than 2 million data, field id, phone, ua, and day. Now, you can use multiple clients to perform Operation Analysis on the table at the same time. A. When I use Client 1 for a long read operation, I use Client 2 for read and write operations respectively:

| 1981-03-12 | 3000.00 | NULL | 10 | | 7839 | KING | PRESIDENT | NULL | 1981-03-12 | 5000.00 | NULL | 10 | | 7844 | TURNER | Salesman | 7698 | 1989-03-12 | 1500.00 | 0.00 | 30 | | 7876 | ADAMS | Clear | 7788 | 1998-03-12 | 1100.00 | NULL | 20 | | 7900 | JAMES | Clear | 7698 | 1987-03-12 | 950.00 | NULL | 30 | | 7902 | FORD | ANALYST | 7566 | 0000-00-00 | 3000.00 | NULL | 20 | | 7934 | MILLER | Clear | 7782 | 1981-03-12 | 1300.00 | NULL | 10 | +-------+---------+-----------

basically completes the modification of the data, you can modify one or more data.modifying multiple or specified criteria needs to be done with a where condition.//Modify All DataUpdate Temp SetName= 'Jack2';//The name of all the data will be modified if multiple columns are modified with "," separateUpdate Temp SetName= 'Jack', age= A;//changing the record fo

Reprint Please specify source: http://blog.csdn.net/l1028386804/article/details/46581769InsertInserting multiple rows of query results into a tableGrammarINSERT into Table_name1 (column_list1) SELECT (column_list2) from table_name2 WHERE (condition)TABLE_NAME1 Specifies the table to insert data into, COLUMN_LIST1 specifies which columns in the table to insert data from, table_name2 specifies that the insert

improves the efficiency of SQL execution. Make sure that the SQL statement executes only the number of rows that need to be modified, where only 3 of the data is updated, while the WHERE clause ensures that only 3 rows of data are executed.If you update multiple values, you only need to modify them slightly:Copy CodeThe code is as follows:UPDATE CategoriesSET Display_order = case IDWhen 1 then 3When 2 then

1. Test 1Create table test (id int, tag int, num int );Insert into test (id, tag, num) values (1, 1, 1), (2, 2), (3, 3 );Update test setTag = 4, num = case when tag = 4 then 4 else 3 endWhere tag = 3;Select * from test;(1) sqlserver2014 results:(2) MySQL results:2. Test 2: sequence of changing the set statementCreate table test (id int, tag int, num int );Insert into test (id, tag, num) values (1, 1, 1), (2

: columns referenced by foreign key columns;to view the properties of a data Table command: SHOW CREATE table Tb_name, from which you can see that the provinces storage engine for the data table is: InnoDBShows the creation of the child table (users), the parent table (provinces), where the PID in the child table is a foreign key column, the ID in the parent table is the reference column, and the English re

Mysql adds multiple foreign keys to the table and adds foreign key cascade constraints to Mysql foreign keys BitsCN.com Mysql adds multiple foreign keys/adds foreign keys/cascading constraints to the table 1. create table 'xh' ('id' int (100) unsigned not null AUTO_INCREM

Note: This document provides two MYSQL instances, multiple instance methods, and so on. LINUX: centOS6.3 64bit (default system development kit installed)Database 1:MYSQL version: mysql-5.0.56PORT: 3306System Directory:/usr/local/mysql3306Database 2:MYSQL version:

In-depth analysis of mysql "on duplicate key update" syntax, mysqlduplicate Mysql "on duplicate key update" SyntaxIf the on duplicate key update is specified at the end of the INSERT statement and the DUPLICATE value appears in a UNIQUE index or primary key after the row is

First, update common usagefirst set up a test environment: DROP TABLE IF EXISTS t_test; CREATE TABLE t_test ( bs bigint () NOT NULL auto_increment, username varchar (?) not NULL, password varchar ( Default NULL, remark varchar (MB) default NULL, PRIMARY KEY (BS) ) Engine=innodb auto_increment=4 DEFAULT CHARSET=GBK; INSERT into T_test VALUES (1, ' Lavasoft ', ' 123456 ', NULL); INSERT into T_test VALUES (2, ' Hello ', null,null); INSER

directly thought of A solution: read Table B in Python and obtain data in the form of {id: age, then, update Table A based on the values of each ID and age.The two tables define and data respectively as follows: Table A definition: Field Type Comment Id Int (11) Name Varchar (20) Age Int (11) Data: 1, name1, 02, name2, 03, name3, 04, name4, 05, name5, 0 Table B definition Field

BKJIA comprehensive report] Sun announced a major version update for the MySQL Enterprise subscription service. Sun has added a Query and analysis tool MySQL Query Analyzer for the MySQL Enterprise Edition to help track and analyze problem codes, solve performance problems and help users significantly increase the spee

Multiple methods for setting passwords for users in mysql: bitsCN.com when you installed Mysql on the machine for the first time, you can access the database anonymously or enter the database as a root without a password. in addition, if you are an administrator, you need to establish and authorize some users, which also involves setting passwords. next we will d

|2|| Lily | F |3|| Lucy | F |4|| Travis | M |5|| Steve | M |6|+--------+-----+------------+6RowsinchSet (0.00sec) MySQL > Delete fromStudentwheresex='F'; Query OK,2Rows Affected (0.01sec) MySQL > Select*from student;+--------+-----+------------+| name | sex | student_id |+--------+-----+------------+| Jim | M |1|| Tom | M |2|| Travis | M |5|| Steve | M |6|+--------+-----+------------+4RowsinchSet (0.00Sec2

Welcome to the Linux community forum and interact with 2 million technical staff. test createtabletest (idint, tagint, numint); insertintotest (id, tag, num) values (, 1), (, 2), (, 3); updatetestsettag4, numcasewhentag4then4else3end Welcome to the Linux community forum and interact with 2 million technical staff> enter 1. test 1 create table test (id int, tag int, num int); insert into test (id, tag, num) values (1, 1, 1, 2), (3, 3); update test set

, the value of the affected row is 1, and if the existing record is updated, the value of the affected row is 2. Note: If column B is also a unique column, insert is equivalent to this UPDATE statement: The code is as follows Copy Code mysql> UPDATE table SET c=c+1 WHERE a=1 OR b=2 LIMIT 1; If the a=1 OR b=2 matches more th

For mysql to use select for update, it must be for InnoDb and be in a transaction. The select conditions are different. The Row-level locks and table-level locks are also used. Because InnoDB defaults to Row-Level Lock, MySQL will only execute Row lock (only Lock the selected data example) If a specified Primary Key is specified explicitly ), otherwise,