Simple and common SQL commands

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1 Database operations

1: Creating Databases: Create DATABASE <name>

2: Display database show databasess (note that there is a last s)

3: Delete Database drop <name>

2 Table Operation:

2.1 Get Table structure: desc <name> or Show columns from <name>

2.2 Delete tables: Drop table <name>

2.3 Insert a piece of data into the table: INSERT into < table name > [(< Field name 1>[,.. < field name n >])] VALUES (value 1) [, (value N)]

Eg:insert into MyClass values (1, ' Tom ', 96.45), (2, ' Joan ', 82.99), (2, ' Wang ', 96.59);

2.4 Enquiry Form:

Query all rows: Select *from <name>

View the first 2 rows of data in table MyClass
Mysql> SELECT * from MyClass ORDER by ID limit 0, 2;

2.5 Deleting a data delete from <name> where id=1

2.6 Modify the data in the table update class set Name= ' BB ' where id=1

DISTINCT clause: Select only a different value, repeat value only once

SELECT DISTINCT < column name > from < table name >

ORDER BY Statement : Sorts records in ascending order.

ORDER BY desc: Sort records in descending order

Select Company,ordernumber from Orders order by Company

SELECT Company, OrderNumber from OrdersORDER BY Company DESC

Insert a piece of data into the table:

INSERT into table_name (column 1, column 2,...) Values (value 1, value 2,....)

INSERT into table name values (value 1, value 2,....)

INSERT into Persons VALUES (' Gates ', ' Bill ', ' xuanwumen ', ' Beijing ')

UPDATE statement:

Update < table name > set < column name >= new value where column name = value

Update class set Name=joy where ID =3

UPDATE person SET Address = ' Zhongshan ", city = ' nanjing ' where LastName = ' wils '

Delete statement: Used to delete a row in a table

Delete from class where city= ' Beijing '

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Simple and common SQL commands