This article brings you an introduction to data operations in MySQL (code examples). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
1. Add data
Ordinary insertion
INSERT INTO info1 VALUES(1,'爱因斯坦','相对论')
There is a situation where only part of the data is inserted, as follows:
INSERT INTO info1(id,name) VALUES(2,'爱迪生')
Insert multiple pieces of data at one time
INSERT INTO info1 VALUES(3,'图灵','人工智能'),(4,'达芬奇','美学'),(5,'尼采','美学');
Query data
SELECT * FROM info1 WHERE id=2;
The queried data can be added to the list as data Medium
2. Delete data
Delete some data
DELETE FROM info1 WHERE name='小泽玛利亚';
Delete all the data in the table Data 1, the structure of the table remains unchanged, but the auto-incrementing primary key of the table is not deleted
DELETE FROM info1;
Delete all data in the table 2, the structure of the table remains unchanged. Delete the auto-incrementing primary key of the table. It is not like delete, where you have to look at each item one by one before deleting it. Instead, it is cleared directly, which can be associated with disk formatting. As follows:
TRUNCATE info1;
3. Modify data
Selective modification 1
UPDATE info1 SET contribution='哲学、美学' WHERE id=5;
Separate multiple columns with commas
UPDATE info1 SET named='达·芬奇',contribution='艺术家、发明家、医学家' WHERE id=4;
4. Query data
1. Simple query
(1) Query all
(2) Query the specified item
SELECT named,country FROM info1
The above is the detailed content of Introduction to data operations in MySQL (code examples). For more information, please follow other related articles on the PHP Chinese website!