SQL Server Database Common commands

To create a database:

Command: Create database name;

Example: Create database student;

To delete a database:

Command: drop database name;

Example: Drop database student;

New table:

Command: CREATE TABLE table name

(Column name data type, column Name 2 ...)

Example: CREATE TABLE Student

(Sname char (), Sid Int)

To delete a table:

Command: DROP table name

Example: Drop table Student

To modify a table structure:

(Insert (new) column)

Command: ALTER TABLE name

Add new column name data type

Example: ALTER TABLE student

Add Sage int

(Delete column)

Command: ALTER TABLE name

Drop Column Name

Example: ALTER TABLE student

Drop Column SID

(Modify column type)

Command: ALTER TABLE name

ALTER COLUMN name data type

Example: ALTER TABLE student

Alter column SID float (floating point type)

(New constraint)

Command: ALTER TABLE name

ALTER COLUMN name new data type

Example: ALTER TABLE student

ALTER COLUMN PK_SID PRIMARY KEY (The new constraint type is a PRIMARY KEY constraint)

(delete constraint)

Command: ALTER TABLE name

Drop Column Name

Example: ALTER TABLE student

Drop Pk_sid

Query table content:

Command: Select the data column name to query

From table name

where filter condition (unable to filter data after grouping)

(Advanced search) "Group By column name (group)

Having filter criteria (only filtered data after grouping)

ORDER BY ordering (the final output of the control data is arranged in a positive order: ASC, Flashback: DESC) "

Example: Select SID

From student

where sid=2

The GROUP by Sid

Having sid=1

ORDER BY DESC "

Inserting data into a table: (the value must correspond to the column one by one)

command: INSERT INTO table name

(column name, column name)

Values

(Value, value)

Example: INSERT INTO table name

(Sname,sid,sage)

Values

(' Zhang San ', 12,15)

To modify data values in a table:

command: Update from table name

Set Column name = new value

Example: Update from student

Set Sname= ' John Doe '

Query mode: (BULK insert multiple data)

command: INSERT into table name (the total number of values must be the same as the total number of columns)

Select value, value, value UNION ALL

Selevt value, value, value

Example: INSERT INTO table name

Select ' Zhang San ', 15,18

Select ' John Doe ', 16,19

View:

Command: CREATE VIEW name

As

Select column

From table name

Example: CREATE VIEW students

As

Select Sname

From student

SQL Server Database Common commands