03:27
kareem
SQL is divided into the following
Ø Data Definition Language (DDL)
Ø Data Manipulation Language (DML)
Ø Data Retrieval Language (DRL)
Ø Transaction Control Language (TCL)
Ø Data Control Language (DCL)
DDL -- create, alter, drop, truncate, rename
DML -- insert, update, delete
DRL -- select
TCL -- commit, rollback, savepoint
DCL -- grant, revoke
CREATE TABLE SYNTAX
Create table <table_name> (col1 datatype1, col2 datatype2 …coln datatypen);
Ex:
SQL> create table student (no number (2), name varchar (10), marks number (3));
INSERT
This will be used to insert the records into table.
We have two methods to insert.
Ø By value method
Ø By address method
a) USING VALUE METHOD
Syntax:
insert into <table_name) values (value1, value2, value3 …. Valuen);
Ex:
SQL> insert into student values (1, ’sudha’, 100);
SQL> insert into student values (2, ’saketh’, 200);
To insert a new record again you have to type entire insert command, if there are lot of
records this will be difficult.
This will be avoided by using address method.
b) USING ADDRESS METHOD
Syntax:
insert into <table_name) values (&col1, &col2, &col3 …. &coln);
This will prompt you for the values but for every insert you have to use forward slash.
Ex:
SQL> insert into student values (&no, '&name', &marks);
Enter value for no: 1
Enter value for name: Jagan
Enter value for marks: 300
old 1: insert into student values(&no, '&name', &marks)
new 1: insert into student values(1, 'Jagan', 300)
SQL> /
Enter value for no: 2
Enter value for name: Naren
Enter value for marks: 400
old 1: insert into student values(&no, '&name', &marks)
new 1: insert into student values(2, 'Naren', 400)
c) INSERTING DATA INTO SPECIFIED COLUMNS USING VALUE METHOD
Syntax:
insert into <table_name)(col1, col2, col3 … Coln) values (value1, value2, value3 ….
Valuen);
Ex:
SQL> insert into student (no, name) values (3, ’Ramesh’);
SQL> insert into student (no, name) values (4, ’Madhu’);
d) INSERTING DATA INTO SPECIFIED COLUMNS USING ADDRESS METHOD
Syntax:
insert into <table_name)(col1, col2, col3 … coln) values (&col1, &col2, &col3 …. &coln);
This will prompt you for the values but for every insert you have to use forward slash.
Ex:
SQL> insert into student (no, name) values (&no, '&name');
Enter value for no: 5
Enter value for name: Visu
old 1: insert into student (no, name) values(&no, '&name')
new 1: insert into student (no, name) values(5, 'Visu')
SQL> /
Enter value for no: 6
Enter value for name: Rattu
old 1: insert into student (no, name) values(&no, '&name')
new 1: insert into student (no, name) values(6, 'Rattu')
SELECTING DATA
Syntax:
Select * from <table_name>; -- here * indicates all columns
or
Select col1, col2, … coln from <table_name>;
Ex:
SQL> select * from student;
NO NAME MARKS
--- ------ --------
1 Sudha 100
2 Saketh 200
1 Jagan 300
2 Naren 400
3 Ramesh
4 Madhu
5 Visu
6 Rattu
SQL> select no, name, marks from student;
NO NAME MARKS
--- ------ --------
1 Sudha 100
2 Saketh 200
1 Jagan 300
2 Naren 400
3 Ramesh
4 Madhu
5 Visu
6 Rattu
SQL> select no, name from student;
NO NAME
--- -------
1 Sudha
2 Saketh
1 Jagan
2 Naren
3 Ramesh
4 Madhu
5 Visu
6 Rattu
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