mysql pivot table

With MySQL or higher, you can add two or more tables to one table. by adding two tables together, you can update the records of one table in the relevant fields and set them to another table. Let's take a few simple examples. Solution 1: 1 column update student s, city c set s.city_name = c.name where s.city_code =

MySQL Union table update and deletion syntax introduction, mysql Union table syntax Preface I believe that when you use mysql in daily use, you may need to update two tables at the same time. I will use two SQL statements in the same transaction to update them separately. In

Mysql cross-table update multi-table updatesql statement summary bitsCN.com suppose we have two tables, one table stores Product information for the Product table, with the Product Price column Price, and the other table is the Pr

Normally, copying and backing up tables is usually done directly by the IDE. But sometimes, some initialization of the data script, before operating the data, it is best to back up the structure of the Operation table, data, not error is placed in a dilemma.So the statement that replicates the table structure and table data comes in handy.> Copy

Create a table in MySQL and create a table in mysql -- Create DATABASE testUse test;Drop table if EXISTS zones;Create table zones(Z_id int primary key auto_increment,Z_name VARCHAR (50) NOT NULL) ENGINE = INNODB;Drop

Prevention and repair of MySQL table corruption 1. analysis of causes of table corruption The following are common causes of mysql table destruction: 1. data files are damaged due to a sudden power failure on the server. 2. force shutdown without shutting down the

Mysql multi-table joint query returns the content of a table. bitsCN.com always reports an error when using mysql statements today. The statement is as follows: SQL code SELECT sapcle FROM SellEnterpriseBaseInfor sebie, SellEnterpriseBaseInforVer sebive, sellapplyperpolicangelist sapcle WHERE 1 = 1 AND sebie. iVer

Implementation of mysql row-column dynamic conversion (join table, cross table), mysql row-column (1) dynamic, applicable to column uncertainty create table table_name( id int primary key, col1 char(2), col2 char(2), col3 int); insert into table_name values(1 ,'A1','B1',9),(

MySQL dynamically creates a table and stores data in sub-tables in bitsCN.com. BEGIN DECLARE '@ I' int (11 ); DECLARE '@ siteCount' int (11 ); DECLARE '@ sqlstr' VARCHAR (2560 ); DECLARE '@ sqlinsert' VARCHAR (2560); // DECLARE the variable above Select count (0) into '@ siteCount' FROM tbl_base_site; // calculates the total number of records in the tbl_base_site table