-sql study of five knowledge systems

1. Create a database

CREATE DATABASE test1;

2. Deleting a database

DROP DATABASE test1;

3. Create a table

CREATE TABLE tabname (userid BIGINT (one) not NULL PRIMARY KEY, username varchar, userpwd varchar, employee_id varchar (Employee_Name), the address varchar (20));

Create an existing table similar table

CREATE TABLE tabname2 as SELECT userid,username,userpwd,address from TabName;

4. Delete a table

DROP TABLE tabname2;

5. Add a column

ALTER TABLE tabname ADD Tel INT (11);

6. Modify a column

ALTER TABLE tabname MODIFY Tel VARCHAR (11);

7. A few simple SQL statements

Insert data: INSERT INTO TabName (Userid,username,userpwd,employee_id,employee_name,address,tel) VALUES (' 001 ', ' XL ', ' [email Protected] ', ' 1406081112 ', ' tester ', ' building 10th, No. 1388th Zhang Dong Road, Pudong, Shanghai ', ' 13612345678 ';

-sql study of five knowledge systems