Mysql add, delete, modify and check basic operations (2)
Three. Modification operation (update)
Syntax : update table name set column = expr [, column = expr …];//Modify the table, change the value of column (an attribute) in the table to expr, of course you can modify multiple at the same time; //change the surname Liu Change age to 20
select * from student where name like '刘%';
update student set age = 20 where name like '刘%';
select * from student where name like '刘%';
//Sentence explanation: 1. Since you want to modify a thing, do you first need to check what its original data looks like; 2. Then modify it; 3. After the last modification, check if you are Successfully modified.
operation result
Four. Delete (delete)
Syntax : delete from table name [WHERE …] [ORDER BY …] [LIMIT …]l; //Delete age equal to 18
select * from student;
delete from student where age =18;
select * from student;
