Article Directory
- foreword
- 1. Delete data records in the table?
- 1. Delete specific data records
- 2. Delete all data records
- Summarize
foreword
Deleting data records is a common operation in data operations, which can delete existing data records in the table. In MySQL, data records can be deleted through the DELETE statement. This SQL statement can be used in the following ways: delete specific data records, delete all data records.
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1. Delete data records in the table?
1. Delete specific data records
Deleting a specific data record in MySQL can be achieved through the SQL statement DELETE, and its syntax is as follows:
DELETE FROM tablename WHERE CONDITION;
In the above statement, the parameter tablename indicates the table name of the data record to be deleted, and the parameter CONDITION specifies to delete a specific data record that meets the condition.
For example: The class led by Martin has graduated, so delete it from the class table!
| mysql> create database school; #create database school mysql> use school; #select database school mysql> create table class(id int UNIQUE AUTO_INCREMENT, name varchar(128) UNIQUE, teacher varchar(64)); #Create table class, specify id field self-growth mysql> insert into class(id, name, teacher) values(1, ' Class One ', 'Martin'),(2,' Class Two ', 'Rock'),(3, ' Class Three ', 'Janny' ); #insert multiple records mysql> delete from class where teacher = 'Martin'; #Delete records through the teacher field or mysql> delete from class where id = 1; #Delete matching records through the id field |
2. Delete all data records
Deleting all data records in MySQL can also be achieved through the SQL statement DELETE, and its syntax is as follows:
DELETE FROM tablename WHERE CONDITION; 或
DELETE FROM tablename；
In the above statement, in order to delete all data records, the parameter CONDITION needs to satisfy all data records in the table tablename, such as id>0; or no keyword WHERE statement.
For example: all the classes led by teachers have graduated, delete them from the class table!
| mysql> create database school; #create database school mysql> use school; #select database school mysql> create table class(id int UNIQUE AUTO_INCREMENT, name varchar(128) UNIQUE, teacher varchar(64)); #Create table class, specify id field self-growth mysql> insert into class(id, name, teacher) values(1, ' Class One ', 'pass'),(2, ' Class Two ', 'wang'),(3, ' Class Three ', 'gou' ); #insert multiple records mysql> delete from class ; #Delete all records directly or mysql> delete from class where id > 0; #Delete all matching records through the id field |
Summarize
as above