CERTAIN QUERIES TO DESCRIBE,ALTER,DISTINCT A TABLE AND INSERT VALUES,DISAPLY A PARTICULAR COLOUMN IN A TABLE ?

TO DESCRIBE

describe table name;

TO INSERT VALUES

to insert values in table employee

create table employee_732

(

e_name char(10),

e_id varchar(5),

e_salary number(6),

e_commission varchar(5)

);

describe employee_732;

to insert values in a table INSERT command is used.for example to insert values in above table

INSERT INTO EMPLOYEE_732 VALUES('ram','a101',15000,'45per');

if we want to insert values in some particular attributes of table employee_668  then

INSERT INTO EMPLOYEE_732(e_name) VALUES('ram');

TO DISPLAY A PARTICULAR COLOUMN

to display a table we use

SELECT*FROM TABLENAME;

to display a particular coloumn we use

SELECT COLOUMN NAME FROM TABLE NAME;

TO ALTER A PARTICULAR TABLE

ALTER TABLE TABLE NAME ADD COLOUMN NAME DATA TYPE(SIZE);

for example to add coloumn e_phnno in above created table 

ALTER TABLE EMPLOYEE_668 ADD E_PHNNO NUMBER(10);

TO GET DISTINCT VALUES

to get distinct values from a table

SELECT DISTINCT*TABLE NAME;

to get distinct values from a particular coloumn

SELECT DISTINCT COLOUMN NAME FROM TABLE NAME;