Review the SQL

Recent review of SQL, found a lot of things have been forgotten, good memory is not as bad as the written wisdom,
SQL: Structured queries language (structed query language)
1. Create a database

CREATE DATABASE my_data_base;

2. Use the library you just created

 use my_data_base;

3. Create a table named teacher

CREATE TABLE Teacher (    VARCHAR)    ,  ageINT,    birthday DATE );

3.1. You can check the table created below

DESC Teacher;

3.2. If you want to delete the created table

DROP TABLE Teacher;

4. Add Data

INSERT  into Teacher (    name, age, birthday)VALUES(    'Tom'29  '1988-09-25'  );

5. Look at how the table looks when you join the data

SELECT *  from teacher;

6. Provide conditions for database search

SELECT *  from  WHERE='Tom';

7. Combine queries with AND and OR

SELECT *  from  WHERE='Tom'and=  ;

8. Looking for data with a value of NULL

SELECT *  from  WHEREisNULL;    

9. Use wildcards to find,% is an alias of any number of unknown characters, _ is an alias of an unknown character

SELECT *  from Teacher WHERE  like ' %o_ ';

10. Use range starting and ending values to query

SELECT *  from Teacher WHERE between  -  and ;

11. Query by using column values to match the collection

SELECT *  from Teacher WHERE  in ('Tom'Tony'   Jone');

12. Reverse the query, not necessarily immediately after the where

SELECT *  from Teacher WHERE  not   in ('Tom'Tony' Jone ');

13. Delete Data

DELETE  from Teacher WHERE  ='Tom';

14. Updating data

UPDATE Teacher SET  ='Mike'WHERE= '  Tony';

15. Add a PRIMARY key

ALTER TABLE Teacher ADD COLUMN INT  not NULL auto_increment First, ADD PRIMARY KEY

15.1. Create primary key, primary key cannot be NULL, cannot be modified

CREATE TABLE teacher (    ID   INTnotNULL  auto_increment,    VARCHAR (ten), age INT,    birthday DATE,         PRIMARYKEY  (id));    

16. Change the name of the table

ALTER TABLE   to student;

17. Changing the column name type of a table

ALTER TABLE  COLUMNVARCHAR(notNULL;

18. Changing only the type of a column does not interfere with its name

ALTER TABLE  COLUMNVARCHAR(+);

19. Remove a column

ALTER TABLE Student DROP COLUMN School;

20. Sorting

SELECT *  from Student ORDER  by DESC;

21. Add function

SELECT SUM (age)  from student;

22. Grouping additions

SELECT SUM  from Student GROUP  by ID;

23. Average function

SELECT AVG (age)  from student;

24. Maximum minimum value

SELECT MAX  from student; SELECT MIN  from student;

25. Specify the number of rows in a column

SELECT COUNT  from student;

26. Choose a different value

SELECT DISTINCT  from student;

27. Limit the number of query results The first number is the start of the query, the second number is the number of returned query results

SELECT *  from 0 1;

Review the SQL