SQL ALTER TABLE Statement
The ALTER TABLE statement is used to ADD, MODIFY or DELETE/DROP columns in the existing table; Also used to ADD/DROP various constraints and triggers on an existing table.
ALTER TABLE - ADD
ADD keyword is used to add columns into the existing table in SQL Server.
ALTER TABLE - ADD Column Syntax
The ALTER TABLE statement is used to add multiple columns to a table in SQL Server.
ALTER TABLE table_name
ADD (column_name1 datatype,
column_name2 datatype
.
.
column_nameN datatype);
ALTER TABLE - DROP Column Syntax
The ALTER TABLE statement is used to drop a column to a table in SQL Server.
ALTER TABLE table_name
DROP COLUMN column_name;
ALTER TABLE - MODIFY Column Syntax
The ALTER TABLE statement is used to modify a column to a table in SQL Server.
ALTER TABLE table_name
MODIFY COLUMN column_name datatype;
EXAMPLE: ALTER TABLE
The 'STUDENTS' Records Table
| ID |
FULL_NAME |
BRANCH |
ADDRESS |
CITY |
COUNTRY |
| 001 |
Kalpana Negi |
CSE |
#42 3rd Floor, 4th Building, East Mumbai |
Mumbai |
India |
| 002 |
Nishant Devid |
Civil |
#543 Main Road, uturn 6th Building |
Delhi |
India |
Example - ADD Column
ALTER TABLE STUDENTS
ADD DOB date;
Result Look Like
| ID |
FULL_NAME |
BRANCH |
ADDRESS |
CITY |
COUNTRY |
DOB |
| 001 |
Kalpana Negi |
CSE |
#42 3rd Floor, 4th Building, East Mumbai |
Mumbai |
India |
|
| 002 |
Nishant Devid |
Civil |
#543 Main Road, uturn 6th Building |
Delhi |
India |
|