At the end of this lesson-
- 1. You will be able to write DDL commands of SQL.
- 2. You will be able to write DML commands of SQL.
- 3. You will be able to write DQL commands of SQL.
Data Definition Language (DDL):
Syntax of SQL Command for Creating Database:
CREATE DATABASE database_name;
SQL Command for creating a database named db_sagc
CREATE DATABASE db_sagc;
Syntax of SQL Command for Creating Table:
CREATE TABLE table_name
( column_name_1 data_type(size),
column_name_2 data_type(size),
.............................
column_name_n data_type(size)
);
SQL command for creating above student_info table-
CREATE TABLE student_info ( Id number PRIMARY KEY, Name text(20), Section text(5), GPA number, City text(20), );
Syntax of SQL Command for Adding Field On Table:
ALTER TABLE table_name ADD
(
new_column_name_1 data_type(size),
new_column_name_2 data_type(size)
);
SQL Command for adding a field named “Contact” in above student_info table-
ALTER TABLE student_info ADD ( Contact text(25) );
After running the SQL command, the structure of student_info table will be like following table-
Syntax of SQL Command for Deleting a Field From Table:
ALTER TABLE table_name DROP column_name;
SQL Command for deleting a field named “City” from the above student_info table-
ALTER TABLE student_info DROP City;
After running the SQL command, the structure of student_info table will be like following table-
Syntax of SQL Command for Deleting a Table From Database:
DROP TABLE table_name ;
SQL Command for Deleting a Table named “student_info” From the Database-
DROP TABLE student_info ;
Data Manipulation Language (DML):
Syntax of SQL Command for Adding a Record On Table:
INSERT INTO table_name (column_name_1, column_name_2, ..) VALUES(Value_1, Value_2, ..) ;
SQL Command for adding a record on a “student_info” table –
INSERT INTO student_info(Id, Name, Section, GPA, City) VALUES( 1, “Ashek", ”A”, 5.00, "Dhaka“ ) ;
After running the SQL command, the student_info table will be like following table-
Syntax of SQL Command for Updating Record of a Table:
UPDATE table_name SET column_name_1=value, column_name_2=value, ... WHERE condition;
SQL command for Updating the value of City field whose Id is 2 –
UPDATE student_info SET City="Khulna“ WHERE Id = 2;
After running the SQL command, the student_info table will be like following table-
Syntax of SQL Command for Deleting Record from Table:
DELETE FROM table_name WHERE condition;
SQL Command for deleting the record whose Id is 1 from student_info table-
DELETE FROM student_info WHERE Id = 1 ;
After running the SQL command, the student_info table will be like following table-
Syntax of SQL command for deleting all the records from a table.
DELETE FROM table_name;
Data query language (DQL):
Syntax of SQL Command for showing all the fields and records of a table-
SELECT * FROM table_name ;
SQL Command for showing all the fields and records from above “student_info” table-
SELECT * FROM student_info;
After running the SQL command, the output table will be like following table-
Syntax of SQL Command for showing particular fields and all the records of a table-
SELECT column_name_1, column_name_2, .. FROM table_name ;
SQL Command for showing the value of Name,Section and GPA fields from the above “student_info” table-
SELECT Name, Section, GPA FROM student_info;
After running the SQL command, the output table will be like following table-
Syntax of SQL Command for showing particular records of a table under condition –
SELECT * FROM table_name WHERE condition ;
SQL Command for showing the records whose GPA is 5.00 from the above “student_info” table-
SELECT * FROM student_info WHERE GPA=5.00;
After running the SQL command, the output table will be like following table-
Lesson Evaluation-
Knowledge Based Questions:
Comprehension Based Questions:
Creative Questions:
Multiple Choice Questions:
Written by,
- Mizanur Rahman (Mizan)
- Lecturer of ICT, Shaheed Bir Uttam Lt. Anwar Girls’ College ,Dhaka Cantonment
- Author at www.edupointbd.com
- Software Engineer at mands IT
- Former Lecturer of ICT, Cambrian College, Dhaka
- Email: mizanjust@gmail.com
- Cell: 01724351470