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How to use SQL statement

1. Database operation: database

Create a database

Syntax:

* createdatabase database name

* createdatabase database name characterset character set

View the database

View all the databases in the database server: showdatabase

View information about a database definition: showcreatedatabase database name

Delete database

Dropdatabase database name

Other database operation commands

Toggle database: use database name

View the database in use: selectdatabase ()

Table operation: table

Field Type

The commonly used types are:

Digital: int

Floating point: double

Character type: varchar (variable length string)

Date type: date (only year, month, day, no hour, minute and second)

Datetime (year, month, day, hour and second)

Boolean type: not supported

Create a tabl

Createtable table name (

Field name type (length) constraint

Field name type (length) constraint

)

View tabl

View all tables in the database: showtables

View table structure: desc table name

Delete tabl

Droptable table name

Modify the table

Altertable table name add column name type (length) constraint;-- modify the table to add columns.

Altertable table name modify column name type (length) constraint;-modify table modify column type length and constraints.

Altertable table name change old column name new column name type (length) constraint;-- modify table modify column name.

Altertable table name drop column name;-- modify table to delete column

Renametable table name to new table name;-- modify table name

Altertable table name characterset character set;-- modify the character set of the table

Insert record

Syntax:

Insertinto table (column name 1, column name 2, column name 3.) values (value 1, value 2, value 3.);-- insert some columns into the table

Insertinto table values (value 1, value 2, value 3.);-- insert all columns into the table

Insertinto table (column name 1, column name 2, column name 3.) valuesselect (column name 1, column 2, column name 3) from table

Insertinto table valuesselect*from table

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