1. Add data
insert into staff values ( 1 , ' Li Bai ' , ' Male ' , ' 701-2-28 ' , ' [email protected] ' , 61 ); /* Insert all fields. Be sure to insert them in order--strings and dates need to be single quotes, numbers are not required, and each field is separated by commas */
/*Be careful not to have less or more field values*/ insert into staff (id,username,gender, age) values ( 5 , ' Meng Haoran ' , ' Male ' , 51 ) /* Insert data by field name, separated by commas */
2. Modify the data
update staff set gender = ' female ' where id = 5 ; /* Conditional modification - modify the table name as staff, gender becomes 'female', and the field is the field with id = 5 */
update staff set gender = ' female ' ,age = 61 where id = ' 1 ' ; /* Modify multiple fields at the same time, separated by commas */
3. Delete data
delete from staff where id = 5 ; /* Delete with condition -- delete all fields with id 5 */
4. Query data ---- key point
select * from staff; /* Query the data of all columns of the table named staff */
select id, username from stall; /* Query the specified column */